CA2684197A1

CA2684197A1 - Iron(ii) catalysts containing diimino-diphosphine tetradentate ligands and their synthesis

Info

Publication number: CA2684197A1
Application number: CA2684197A
Authority: CA
Inventors: Alexandre Mikhailine; Friederike Freutel; Christine Sui-Seng; Nils Meyer; Robert H. Morris; Parasekevi Olympia Lagaditis
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-10-30
Filing date: 2009-10-30
Publication date: 2011-04-30

Abstract

New hexa-coordinate iron (II) complexes comprising compounds of formula (I) are described. These compounds comprise a tetradentate ligand with donor atoms comprising nitrogen and phosphorus. These complexes are shown for the first time to be useful catalysts for the hydrogenation of ketones, aldehydes, or imines to produce alcohols or amines, and the asymmetric hydrogenation of prochiral ketones or imines to produce non-racemic alcohols or amines. The source of the hydrogen can be hydrogen gas or a hydrogen-donating molecule such as isopropanol or hydrogen-donating mixture such as formic acid and an amine depending on the structure of the catalyst. In certain embodiments, the axial ligands on the catalyst comprise organonitrile ligands, carbonyl ligands, isonitrile ligands, or combinations thereof. The catalysts and the preparation thereof are disclosed. A reaction using phosphine and diamine precursors that is templated by the iron ion is the preferred route to the catalysts.

(see formula I)

Description

IRON(II) CATALYSTS CONTAINING DIIMINO-DIPHOSPHINE
TETRADENTATE LIGANDS AND THEIR SYNTHESIS
[00011 This application claims the benefit of the priority date of US
Provisional patent application No. 61/193147, filed October 31, 2008 and entitled Iron(Ii) Catalysts Containing Diimino-Diphosphine Tetradentate Ligands And Their Synthesis, the entire subject matter of which is incorporated herein by reference.

TECHNICAL FIELD
[00021 The present invention relates to catalytic materials for hydrogenation or asymmetric hydrogenation. In particular, the invention relates to iron (II) complexes containing tetradentate diimino-diphosphine (P2N2) ligands for the catalytic hydrogenation or asymmetric hydrogenation of carbonyl groups for use in preparing alcohols or non racemic alcohols, respectively.
Imine groups can similarly be hydrogenated or asymmetrically hydrogenated to provide amines, or non-racemic amines, respectively. These alcohols and amine products are important raw materials in the manufacturing of chemical products, pharmaceuticals, fragrance and flavours.

BACKGROUND
[00031 Asymmetric hydrogenation is an important method for generating single enantiomer molecules that include intermediates and fine chemicals with applications in the pharmaceuticals, biotechnology, agrochemical, food, flavours, essential oils, personal care and advanced materials industries. Each enantiomer may have quite different properties and effectiveness. The use of a drug molecule as a single enantiomer reduces the risk of negative effects of a racemate, increases efficacy and accuracy of dosage, reduces the dosage compared to racemates by one half, with a subsequent reduction in cost and waste, environmental burden including agricultural and human waste run-off. This is particularly true since the US Food and Drug Administration, the European Committee for Proprietary Medicinal Products and other regulatory authorities have required characterization of enantiomers in proposed marketable drug products. Examples of some of the top selling drug products that are chiral are: LipitorTM, ZocorTM, ZyprexaTM, NorvascTM, ProcritTM, PrevacidTM, NexiumTM, PlavixTM, AdvairTM
and ZoloftTM. In 2003 the total global sales for these products amounted to 48.3 billion dollars.

[00041 In the biotechnology sector the ability to synthesize enantiomerically pure amino acids, peptides and proteins is of great value. In the agrochemical business about 25% of the members of several classes of pesticides and herbicides exist as enantiomers. Currently the largest scale asymmetric hydrogenation process is the production of the S enantiomer of MetalochlorTM
[00053 Volatile, enantiomerically pure alcohols are particularly valuable in the flavours and fragrances industries where each enantiomer provides a distinctive olfactory sensation. They are playing an increasingly important role in aromatherapy.

[00061 Single enantiomer helical molecules impart important optical, electronic and magnetic properties to materials and nanomaterials with applications in switches, motors, sensors, polarizers and displays.

[00071 In the hydrogenation of complex molecules, the selectivity and activity of the process is dependent on the catalyst structure. This structure must interact with the substrate to provide the diastereomeric transition state of lower energy that leads to the required enantiomer.

(00081 Conventional asymmetric hydrogenation catalysts utilize platinum group metals (PGM) ruthenium, osmium, rhodium, iridium, palladium or platinum (De Vries et al., "Handbook of Homogeneous Hydrogenation" Wiley-VCH, volumes 1-3, 2007). Their ability to activate hydrogen gas toward addition to organic compounds is well known. However, these metals present potential

2 toxicity problems and prolonged usage of pharmaceuticals containing traces of these metals might lead to harmful bio-accumulation. PGM are expensive and thereby add to the cost of the final product. In addition, they are in limited supply and will decrease in availability over time.

[00091 The direct hydrogenation of carbonyl and/or imine groups in an organic molecule using hydrogen gas is now becoming the preferred "green"
method because no waste is produced and the separation of product is easier.
Hydrogen is expected to be an even more abundant feedstock as it is used more as a green fuel. In a complimentary way, the catalytic hydrogenation or asymmetric hydrogenation of carbonyl and/or imine groups in an organic molecule by transfer from a hydrogen-donating molecule or mixture has the advantage of operational simplicity by avoiding the use of pressurized hydrogen (Gladiali et al., "Asymmetric transfer hydrogenation: chiral ligands and applications," Chem.
Soc.
Rev. 35 (2006) pp 226-236).

[000101 The reduction of ketones is one of the fundamental reactions in the chemistry field and is used in many chemical transformations towards various products. Asymmetric reduction of the carbonyl group was achieved in the past using chiral catalysts that are based on platinum group metals (PGM) such as ruthenium, rhodium, iridium, palladium or platinum. Usually `PrOH or H2 are used as a reducing agent in those transformations when they are activated by the metal-catalysts. The activation is normally produced via the in situ formation of the catalyst from pre-catalyst by the addition of a strong base.

[000111 Reduction catalysis utilizing molecular hydrogen is more attractive compared to the reduction with 'PrOH because of the low price of hydrogen gas, product purification simplicity and waste elimination. Reduction catalysis by hydrogen transfer from 'PrOH is preferred when pressurized hydrogen gas is not available or convenient.

3 [000121 Chiral alcohols and amines that are produced by the asymmetric hydrogenation or asymmetric transfer hydrogenation of ketones and imines, respectively, are extensively used in the synthesis of pharmaceuticals, agricultural chemicals, fragrances and materials. A non-limiting list of the examples of such compounds is presented below:

HO * OH OH
cj__~- N

OH ' Ph HN

4 5 [000131 Product 1 can be used in preparation of the (+)-compactin, an HMG-CoA-reductase inhibitor. Product 2 can be used in the synthesis of 2,4-diaminoquinazoline derivatives which are possible SMN2 promoter activators which can be used in the treatment of spinal muscular atrophy. Product 3 may be used as a synthetic building block of the highest selling drug Fluoxetine (prozac ). Product 4 may be used as a chiral synthetic intermediate in preparation of the benzazepine dopamine antagonist Sch 39 166.

[000141 Although some PGM catalytic systems have enzyme-like enantioselectivities and activities, their toxicity and high price make them unattractive for some industrial synthetic transformations.

[0 00151 Attempts have been made to solve this problem. For example, Gao et al. in 1996 in the journal Polyhedron (Gao et al. "Synthesis and characterization of iron(2+) and ruthenium(2+) diimino-diphosphine, diamino-diphosphine and diamido-diphosphine complexes,"Polyhedron 1 (1996), pp.
1241-1251) reported the synthesis of iron complexes with tetradentate ligands.
The use and application of their iron complexes towards hydrogenation was not disclosed. They reported the synthesis of two iron complexes with diphosphinediimine ligands 6 and 7: trans- [Fe(NCMe)2(6)](C1O4)2 and trans-[Fe(NCMe)2(7)] (C1O4)2 -N nN~
/ PPh2 Ph2P \ /
6n=2 7n=6 [000161 They also reported the iron complex with the diphosphinediamine ligand 8.
/--\
NH HN

\ /
CPPh2 Ph2P \ /

[000171 Further, Gao et al. in 1996 in the journal Organometallics (Gao et al., "A ruthenium(ii) complex with a c-2-symmetrical diphosphine/diamine tetradentate ligand for asymmetric transfer hydrogenation of aromatic ketones, "Organometallics 15 (1996), pp. 1087-1089) disclosed that ruthenium complexes with the enantiopure ligands 9 ((R,R)-cyP2N2) and 10 are catalysts for the asymmetric transfer hydrogenation of ketones with the latter displaying superior activity and selectivity. Rautenstrauch et al. (Rautenstrauch et al., "Hydrogenation versus Transfer Hydrogenation of Ketones: Two Established Ruthenium Systems Catalyze Both," Chem. Eur. J. 9 (2003), pp. 4954-4967;
6,878,852 B2 5/2005 to Rautenstrauch et al.) showed that similar ruthenium complexes are active for the hydrogenation and asymmetric hydrogenation of ketones.

Q Q
N N- NH HN-/ PPh2 Ph2P / \ C~PPh2 Ph2P /

[00018] Boaz et al. (6,690,115 B2 7/2003 to Boaz et al.; 2006/0135805 Al to Boaz et al.) made ketone hydrogenation catalysts based on PG metals such as Ru and Rh in complexes of PNNP ligands of the type 11. Here the iron is part of the ferrocenyl substituent on the ligand which is known in the art to provide selectivity and sometimes activity to a PG metal catalyst.

R /D\ R
NH HN R
n Rn~ PPh2 Ph2P V

Rn Fe Rn Fe [000191 Chen et al. (Chen et al., "Asymmetric transfer hydrogenation of ketones catalyzed by chiral carbonyl iron systems," Huaxue Xuebao 62 (2004), pp.
1745-1750) reported an asymmetric transfer hydrogenation system where one of the compounds 10, 12 or 13 of the type P-NH-NH-P are added to [HFe3(CO)1 11 to generate in situ catalysts for the transfer of hydrogen from isopropanol to ketones but the activity was low and the nature of the active catalyst was thought to be a cluster containing the three irons. The structure of this catalyst remains unknown. Other iron precursors Fe(CO)5 and [Fe(C5H5)(CO2]2 did not lead to active catalyst mixtures.

Ph Ph NH HNH HN
\ / PPh2 Ph2p zp \ / PPh2 Ph2p 2P \ /

[ 0 0 0 2 01 Bianchini et al. (Bianchini et al., "Chemoselective Hydrogen-Transfer Reduction of alpha,beta-Unsaturated Ketones Catalyzed by Isostructural Iron(II), Ruthenium(II), and Osmium(II) cis Hydride eta(2)-Dihydrogen Complexes," Organometallics 12 (1993), pp. 3753-3761) reported that iron complexes with a tetradentate PP3 ligand were active for the non-asymmetric hydrogenation of olefins under mild conditions.

[00021] Enthaler et al. (Enthaler et al., "Biomimetic transfer hydrogenation of ketones with iron porphyrin catalysts," Tet. Lett. 47 (2006), pp. 8095-8099) reported that in situ-generated iron complexes of achiral porphyrin ligands are somewhat active for the hydrogenation of ketones but no asymmetric hydrogenation reaction was possible because of the lack of a chiral ligand.
[000221 Casey's group (Casey et al., "An efficient and chemoselective iron catalyst for the hydrogenation of ketones," J. Am. Chem. Soc. 129 (2007), pp.
5816-5817) reported that an achiral complex of the type Fe(arene-OH)H(CO)2 is a hydrogenation catalyst but not an asymmetric hydrogenation catalyst for ketones and imines at room temperature. It also catalyzes the hydrogenation of acetophenone by transfer from isopropanol. The complex [NMe4][Fe3H(CO)11]
catalyzes the complete conversion of ketones to alcohols at 80-100 C within 1-h by using alcohols as the reductant (Jothimony et al. "Mechanism for transfer hydrogenation of ketones to alcohols catalyzed by hydridotriiron undecacarbonylate anion under phase transfer conditions," 52 J. Molec. Cat.
(1989), pp. 301-304) but this is not an asymmetric reduction. Bart et al.
(Bart et al., " Preparation and molecular and electronic structures of iron(0) dinitrogen and silane complexes and their application to catalytic hydrogenation and hydrosilation," J. Am. Chem. Soc. 126 (2004), pp. 13794-13795) have reported achiral iron catalysts that hydrogenate olefins under mild conditions.
[000231 Thus, there is a need for new catalysts for hydrogenation, asymmetric hydrogenation, transfer hydrogenation, and asymmetric transfer hydrogenation which do not require the use of PGMs.

SUMMARY OF THE INVENTION
[00024] In one aspect, there is a provided a hexa-coordinate iron (II) complex comprising a compound of formula (I):

R5 R6 R7 R$ m+

R4 N, L1 "N~R
A 'P~ L2 p A
I IX

(I) wherein each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two RI groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;
[000251 A is selected from:
(i) c ;and ( ) (000261 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

[000271 each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

[000281 each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from and F\

each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
[ 0 0 0 2 91 L1 and L2 are independently selected from the group consisting of CO; hydride; pyridine and derivatives thereof, imidazole and derivatives thereof;
halide ion; NCR, CNR and "OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR`wherein Ra, Rb, and Rc are independently selected from the group consisting of H and C1-C2 alkyl; and R (CO)Rd wherein Rc and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl;

[000301 in represents the charge of the compound of formula (I) and is 0, +1, or +2; and when in is +1 or +2, the iron (II) complex comprises at least one counter ion to counterbalance the charge of the compound of formula (I);

[000311 with the proviso that when A is f , then at least one of L1 and L2 must be selected from the group consisting of CO and CNR, wherein R is as defined above.

[000321 In another aspect, there is provided a process for the preparation of a hexa-coordinate iron (II) complex of formula (I), the process comprising reacting a phosphinaldehyde precursor of formula (V):

OH 2+
R12P. -fLR4 HO A
(V) wherein [000331 each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

[00034] A is \ R3 "n`
[000351 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;
[ 0 0 0 3 61 each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;
[000371 with a diamine of formula (VI):

R * R

(VI) wherein [000381 each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from * * and [ 0 0 0 3 91 each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
[000401 in the presence of-[000411 an iron (II) salt;
[000421 a ligand selected from the group consisting of CH3CN; pyridine and derivatives thereof; and imidazole and derivatives thereof, and [000431 a strong base;
[000441 to form the compound of formula (I) R5 R6 R7 R8 rp+
* 4 Ra /N. Lt R
A- P"0'111 L i 2P,A

(I) [00045] wherein A, R1-R8, and n are as defined above, [00046] m is +2, [000471 L' and L2 are both CH3CN; pyridine or a derivative thereof; or imidazole or a derivative thereof;

[000481 and adding at least one counter ion to counterbalance the charge of the compound of formula (I).

[000491 In another aspect, there is provided, a process for preparing an alcoholic compound wherein said process comprises a step of preparing the alcoholic compound by reducing a ketone or aldehyde with the reaction of hydrogen or a compound donating hydrogen in the presence of a hexa-coordinate iron (II) complex of formula (I), with the proviso that the ketone is not an unsubstituted cycloalkanone.

[000501 In still another aspect, there is provided a process for preparing an amine compound wherein said process comprises a step of preparing the amine compound by reducing an imine with the reaction of hydrogen or a compound donating hydrogen in the presence of a hexa-coordinate iron (II) complex of formula (I).

[000511 In yet another aspect, there is provided a hydrogenation catalyst comprising a hexa-coordinate iron(II) complex of formula (I) R5 R6 R7 R8 m+

-,N L. N~R
L2' A

R' RI RI RI
(I) [000521 wherein a trans coordination geometry is achieved at iron through nitrogen and phosphorus donor bonds of a tetradentate diimino-diphosphine templated ligand of the formula (II):

R12P-A-C(R4)=N-C*(RSR6)-C*(RR)-N=C(R)-A-PR2 (II) and L' and L2 are in an axial coordination above and below the templated ligand, respectively, [000531 wherein the tetradentate diimino-diphosphine templated ligand is the reaction product of a phosphinaldehyde precursor of formula (V) OH 2+
R12P'A NfCR4 HO A
(V) [000541 and a diamine precursor of formula (VI) R6_R8 (VI) wherein [000551 each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;
A is selected from:
( R3 ri/;

[000561 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

[000571 each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

[000581 each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from and [000591 each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;

[000601 L1 and L2 are independently selected from the group consisting of CO; hydride; pyridine and derivatives thereof, imidazole and derivatives thereof;
halide ion; NCR, CNR and "OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR`wherein Ra, Rb, and R are independently selected from the group consisting of H and CI-C2 alkyl; and Rc(CO)Rd wherein Rc and Rd are independently selected from the group consisting of CI-C8 alkyl, aryl, and heteroaryl;

[000611 m represents the charge of the compound of formula (I) and is 0, +1, or +2; and when m is +1 or +2, the iron (II) complex comprises at least one counter ion to counterbalance the charge of the compound of formula (I);
X
[000621 with the proviso that when A is U"~" then at least one of L' and L2 must be selected from the group consisting of CO and CNR, wherein R is as defined above.

[000631 In still another aspect, there is provided a process for the preparation of a hexa-coordinate iron (II) complex, the process comprising reacting a phosphinaldehyde precursor of formula (V):

OH 2+
R12P- A Ra R4 A~PR12 HO
(V) wherein [0 00641 each R1 is independently selected from the group consisting of aryl, heteroaryl, CI-C8 alkyl, C2-C8 alkenyl, CI-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

R2 ~s Ais R3 n [000651 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

[000661 each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

with a diamine of formula (VI):

R6 * * R8 (VI) wherein [00067] each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from and each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;

[0 00681 in the presence of-[0 00691 an iron (II) salt;
[ 0 0 0 7 01 a ligand selected from the group consisting of CH3CN; pyridine and derivatives thereof; and imidazole and derivatives thereof; and [00071] a strong base;
[000721 and further reacting the reaction product of the foregoing steps with CO to produce a compound of formula (VIIIa):
7 m+

* * 4 R4 1Lt R
F
A, PI L p L

(VIIIa) [0 0 0 7 3 ] wherein A, R1-R8, and n are as defined above, L1 is CO, L2' is Br, and m is +1;
[0 0 0 7 4 ] and adding a counter ion to counterbalance the charge of the compound of formula (VIIIa).
[00075] A process for preparing a phosphonium dimer of formula (XIII) is provided:

[HO:0H] \Ri (XIII) [000761 wherein R1 is selected from the group consisting of C1-C8 alkyl, C1-C8 substituted alkyl, cycloalkyl, and substituted cycloalkyl, and X
is selected from the group consisting of Br and I, the process comprising:
[0 00771 reacting a compound of formula (XI):

[ 0 0 0 7 8] HPR'2 (XI) [000791 wherein R1 is as defined above;
[000801 with a compound of formula (XII):
0 rRe X _ Re (XII) (000811 wherein X is as defined above, and Re is C 1-C8 alkyl, or the two Re can combine to form a C2-C3 linear alkyl diradical;

[0 0 0 8 2 ] and heating the reaction product in the presence of water to form the phosphonium dimer of formula (XIII).

DETAILED DESCRIPTION
[000831 Iron (II) complexes with PNNP donor ligands as catalytic materials for the hydrogenation, asymmetric hydrogenation, transfer hydrogenation, and/or asymmetric transfer hydrogenation of ketones and imines are disclosed.

[000841 The asymmetric hydrogenation technology described herein that provides a specified enantiomer enables a more economical, safer, efficient, and greener chemical way to generate compounds that are significantly enriched in the required enantiomer.

[000851 As noted above, conventional asymmetric hydrogenation catalysts utilize platinum group metals (PGM) ruthenium, osmium, rhodium, iridium, palladium or platinum (De Vries et al., "Handbook of Homogeneous Hydrogenation" Wiley-VCH, volumes 1-3, 2007). PGM are expensive and thereby add to the cost of the final product. In addition, they are in limited supply and not readily available. By contrast, iron is inexpensive, abundant and biocompatible. An unexpected feature of the disclosed catalysts is the high activity that they display in the activation of hydrogen gas toward the hydrogenation of ketones and in the activation of hydrogen-donor molecules such as isopropanol toward the transfer hydrogenation of ketones and imines.
[000861 In one embodiment, there is provided a hexa-coordinate iron (II) complex comprising a compound of formula (I):

R6 R7 M+

* * 4 R4 1 L t `Nzz~ R
PIL2~P,A

R1 R1 R Rt (I) wherein [000871 each Rt is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

[000881 A is selected from:
'vl; and (,s R3 inss"

[000891 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

[000901 each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

[000911 each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from x , and each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;

[000921 L' and L2 are independently selected from the group consisting of CO; hydride; pyridine and derivatives thereof; imidazole and derivatives thereof;
halide ion; NCR, CNR and -OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR N wherein Ra, Rb, and Rc are independently selected from the group consisting of H and C1-C2 alkyl; and R (CO)Rd wherein R and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl;

[000931 m represents the charge of the compound of formula (I) and is 0, +1, or +2; and when m is +1 or +2, the iron (II) complex comprises at least one counter ion to counterbalance the charge of the compound of formula (I);
[000941 with the proviso that when A is then at least one of L' and L2 must be selected from the group consisting of CO and CNR, wherein R is as defined above.

[000951 In another embodiment, a trans coordination geometry is achieved at iron through nitrogen and phosphorus donor bonds of a tetradentate diimino-diphosphine templated ligand of the formula (II):

RI2P-A-C(R4)=N-C*(R5R6)-Cs(R7R8)-N=C(R4)-A-PR12 (II) [000961 and L' and L2 are in an axial coordination above and below the templated ligand, respectively.

[0 0 0 9 7 ] In one embodiment, the at least one counter ion is selected from BF4 ; PF6 ; SbF6 ; C104; CH3SO3-; CF3S03 ; C6H5SO3 ; p-CH3C6H4SO3-; FeC142-;
FeBr42 B(R*)4 , wherein R* is selected from phenyl, C6H3(CF3)2 and C6F5;
halides; pseudohalides; Cl-C8 alkoxides; and aryloxides. In another embodiment, the at least one counter ion is BF4 In another embodiment, the at least one counter ion is BPh4-.

[000981 In another embodiment, Rl is substituted or unsubstituted aryl. In other embodiments, R1 is phenyl.

[0 0 0 9 9 ] In another embodiment, A is S . In another embodiment, R4 is H. In yet another embodiment, R5, R6, R7 and R8, together with the carbon atoms to which they are attached, combine to form., . In certain embodiments, the chiral carbon atoms denoted by asterisks both have an R
configuration. In other embodiments, the chiral carbon atoms denoted by asterisks both have an S configuration.

(R2 [0001001 In still another embodiment, A is R3 n' . In another embodiment, R4 is H. In another embodiment, R2=R3=H. In yet another embodiment, n=1.

[0001011 In another embodiment, R5=R8=substituted or unsubstituted aryl and R6=R7=H. In another embodiment, R5=R8=phenyl. In still another embodiment, the chiral carbon atoms bearing the substituents R5 and R6, and R7 and R8, respectively, both have an R configuration. In another embodiment, these chiral carbon atoms have an S configuration.

[0001021 In another embodiment, R4=R5=R6=R7=R8=H.

[0001031 In another embodiment, L' and L2 are CH3CN. In still another embodiment, L' is CH3CN and L2 is selected from CO or CNR, wherein R is Cl-C8 alkyl. In another embodiment, L2 is CNtBu.
[0001041 In another embodiment, the hexa-coordinate iron (II) complex comprises a compound having the structure:

Phi NCCH3 3 2+
CfNp' F P
Ph21 Ph2 (III).

[0001051 In another embodiment, the chiral carbon atoms denoted by asterisks both have an R configuration. In another embodiment, the chiral carbon atoms denoted by asterisks both have an S configuration.

[0001061 As noted above, the A symbol represents the bridging group -(CR2R3),,. In one embodiment, n is 1, R3 is H and R2 is H. In other embodiments, R3 is H and R2 may be selected from aryl or C1-C8 alkyl, each of which may be optionally substituted. When R2 96R3, the carbon bearing these substituents is chiral and may be enantiopure.

[0001071 In other embodiments, n may be 2, and A is then -CR2R3CR2R3-.
In further embodiments, n may be 3 and A is then -CR2R3CR2R3CR2R3-. In one embodiment, all R3 may be H. In another embodiment, each R3 may be different.
Likewise, the R2 groups may be the same or different.

[0001081 In another embodiment, R5, R6, R7 and R8 can be selected to produce enantiopure structures. For instance, the cyclohexyldiyl structure noted above may be present as the (R,R) or (S,S) enantiopure isomer (having regard to the chiral carbon atoms denoted by asterisks).

[0001091 The various chemical terms used herein are to be given their ordinary meaning as would be understood by persons skilled in the art, unless provided otherwise.

[0001101 The following chemical terms presently described apply to all compounds and processes disclosed herein, unless provided otherwise.

[0001111 A "templated ligand" is a molecule that forms from precursor parts that coordinate to a metal ion at geometrically defined positions such as octahedral or square planar, for example, and bond together. The metal ion acts as template for the formation of this ligand. Given the same reaction conditions, but in the absence of the metal template, the precursor parts usually either do not react, or do react but form a mixture of products, none of which have the structure of the templated ligand.

[0001121 The compounds of formula (I) disclosed herein are referred to herein as "catalysts". However, it will be understood by a person of skill in the art that further study may reveal that these compounds are in theory "pre-catalysts" and are converted to an active form during the hydrogenation reactions.
[0001131 The term "C 1-C8 alkyl" as used herein either alone or in combination with another substituent means acyclic, linear or branched chain alkyl substituent containing from one to eight carbons and includes for example, methyl, ethyl, 1-methylethyl, 1-methylpropyl, 2-methylpropyl, butyl and the like.
[0001141 The term "C2-C8 alkenyl", as used herein, either alone or in combination with another radical, is intended to mean an unsaturated, acyclic linear chain radical containing from two to eight carbon atoms, at least two of which are bonded to each other by a double bond. Examples of such radicals include, but are not limited to, ethenyl (vinyl), 1-propenyl, 2-propenyl, and 1-butenyl. The alkenyl groups may contain any number of double bonds.

[0001151 The term "aryl" as used herein, either alone or in combination with another substituent, means an aromatic monocyclic system containing 6 carbon atoms or an aromatic bicyclic system containing 10 carbon atoms. The rings may have substituents including alkyl groups or alkoxy groups. For instance, a phenyl ring may have substituents such as in the 3 and 5 positions, or 2 and 6 positions, or in the 4 position. The term "aryl" includes but is not limited to a phenyl, tolyl (substituted aryl) or naphthyl group.

[0001161 The term "heteroaryl" as used herein, either alone or in combination with another substituent means a 5, 6, 7, or 8-membered unsaturated heterocycle containing one oxygen or sulfur or from one to 4 nitrogen heteroatoms and which form an aromatic system. For example, the term "heteroaryl" includes a furyl, pyridyl, or quinolinyl group.

[0001171 The term "cycloalkyl" as used herein, either alone or in combination with another substituent, means a cycloalkyl substituent that includes for example, but is not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl [0001181 The term "alkoxy" as used herein, either alone or in combination with another radical, means the radical -O-(C1_r) alkyl wherein the alkyl group contains 1 or more carbon atoms, and includes for example methoxy, ethoxy, propoxy, 1-methylethoxy, butoxy, cyclohexyloxy and 1,1-dimethylethoxy.
"Alkoxide" refers to the radial -O-(C1_õ) alkyl bearing a negative charge.
[0001191 The term "aryloxy" as used herein, either alone or in combination with another radical, means the radical -0-aryl wherein aryl is defined as above, such as phenyl.

[00012 01 The term "aromatic diradical" includes groups such as benzo, as well as naphthyl diradical, binaphthyl diradical, and bisoxynaphthyl diradical as derived from BINOL. The term "branched alkyl diradical" includes groups such as 1,4-dimethylbutanediyl. In one aspect, the branched alkyl diradical may have between 3 and 8 carbon atoms. Such diradicals may be enantiopure. The term "linear alkyl diradical" includes C2-C4 linear alkyl diradicals such as 1,2-ethylene, 1,3-propylene, and 1,4-butylene.

[0001211 The term "diradical that spans a wide bite angle" refers to aromatic diradicals such as naphthyl diradicals or tricyclic groups such as the 4,5-diradical of 9,9-dimethylxanthene and other groups described in the article by Kramer et al.
Acc. Chem. Res. 2001, 34, 895-904, the contents of which are hereby incorporated herein by reference.

[0001221 The term "halogen" refers to F, Cl, Br, and I. The term "halide ion" refers to a halogen atom bearing a negative charge.

[00012 31 The term "pseudohalide" refers to anions that behave chemically like halides. These include OCN, SCN, CN- and NNN.

[0001241 As noted above, certain of the R1-R8 groups may be optionally substituted. Those of skill in the art will understand that a suitable substituent includes, for example, methyl substituents on aryl groups to generate tolyl or xylyl groups and the like. Suitable substituents for aryl, heteroaryl, and cycloalkyl functionalities include C1-C8 alkyl, branched or linear, alkoxy or halogen atoms. Suitable substituents for each "R" group mentioned in the claims include methyl, isopropyl, tertiary-butyl and phenyl.

[0001251 It is to be understood that a suitable substituent is a substituent that does not interfere with the formation of the desired product by the claimed processes and methods disclosed herein. It is understood, of course, that the R
groups defined herein (R'-R8, etc.) will not contain any substitution or substitution patterns which are sterically impractical and/or synthetically non-feasible.

[0 0 012 61 As noted above, the L1, L2 symbols, taken separately, represent simultaneously or independently CO; hydride; pyridine and derivatives thereof, including but not limited to 4-picoline or 3-picoline; imidazole and derivatives thereof, including but not limited to N-methyl imidazole; halide ion; NCR, CNR
and "OR, wherein R is independently selected from aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted;
RaRLR N wherein Ra, Rb, and R' are independently selected from H and C1-C2 alkyl; and Rc(CO)Rd wherein Rc and Rd are independently selected from C1-C8 alkyl, aryl, and heteroaryl.

[0001271 The charge on the complex (m) depends on the nature of the P-N-N-P ligand and the ligands Ll and L2 and can vary from 0 to +2. The charge m+
on the metal is 2+ when the ligands Ll and L2 are neutral, 1+ when one of Ll or L2 is anionic, 0 when both L1 and L2 are anionic.

[0001281 To counterbalance this charge in the metal complex salt, at least one counter ion is present. The term "counter ion" refers to an ion that is associated with the compounds of formula (I) disclosed herein in order to counterbalance the charge of the compound of formula (I) in the iron (II) complex.
Such counter ions may include for example anions selected from the group comprising BF4 PF6 ; SbF6 C1O4 CH3SO3 CF3SO3 C6H5SO3 ; p-CH3C6H4SO3 FeC142 FeBr42 B(R*)4 wherein R* is selected from phenyl, C6H3(CF3)2 and C6F5; halides; pseudohalides; alkoxides such as C1-C8 alkoxides and aryloxides such as phenoxide.

[00012 91 Compounds donating hydrogen include lower alcohols such as methanol, ethanol, propanol, 2-propanol or butanol, and formic acid.

[00013 01 In particular the enantiopure complex (i) is useful for hydrogenation of ketones and imines, asymmetric hydrogenation of prochiral ketones and imines, and is useful as a precursor for the complex (ii). Complex (i) has been crystallized as the BF4 and the BPh4 salt (see Example 1) and characterized by elemental analyses, NMR, IR, MS and single crystal X-ray diffraction. The (S,S)-enantiomer of complex (i) has also been prepared.

NCCH3 2+
Ph Ph N,,'' ~N\
C Fe Ph2 I Ph, (i) [0001311 The performance of the catalyst (i) was tested on 10 different aromatic ketones according to the reaction Scheme 1 O Catalyst (i)/H2(l0atm) /KO`Bu/zPrOH HO H
R,I~R" S/C/B 200/1/15; T=35 C. R'" * 'R
(S) where S:C:B refers to the substrate to catalyst to base ratio. The procedure of the catalytic runs was performed as follows: (a) Table 1. The hydrogenation of ketones catalyzed by (i) and base KOtBu (S/C/B=
200/1/15) in 9 mL isopropanol at 35 C under 10 atm H2.
e.e.
Entry Substrate Time Conv. (S) (min) (%) (%) I Ph-CO-Me 30 40-90 81 2 Ph-CO-Et 25 35-80 92 3 Ph-CO-iPr 30 5 99 Ph-CH2-CH2-CO- 90/56 4 Me 25/50 -98 1 (4'-C1C6H4)-CO-Me 20 55-91 91 (4'-MeOC6H4)-6 CO-Me 20 60-94 88 (3'-C1C6H4)-CO-7 Me 180 10-45 82 (3'-BrC6H4)-CO-8 Me 30 5-30 86 (2'-C1C6H4)-CO-9 Me 30 35-58 75 1-Acetonaphthone 360 55-96 95 [0001321 In the N2 glovebox, the iron complex (10 mg, 0.007 mmol), KOtBu (12.3 mg, 0.107 mmol) and the substrate were separately dissolved in the 3 mL
of 2-propanol, each. The resulting solutions in the order substrate, then base, and then catalyst were injected into a 50 cm3 Parr hydrogenator reactor at the desired pressure and temperature, maintained by use of a Fischer Scientific Isotemp 1016D water bath under a hydrogen atmosphere..

[0001331 Complex (ii), shown below, has been crystallized as the BPh4' salt (see Example 2) and characterized by elemental analyses, NMR, IR, MS and single crystal X-ray diffraction. The (SS)-enantiomer has also been prepared and completely characterized. Enantiopure complex (ii) is useful for the transfer hydrogenation of ketones and imines and asymmetric transfer hydrogenation of prochiral ketones and imines.

Ph Ph -1 2+
N
P:,~
Ph, C Ph, III
O

(ii) Table 2. The transfer hydrogenation of ketones to the (S) alcohols catalyzed by (ii) and base KOtBu (S/C/B= 1600/1/8 unless specified) isopropanol at 22 C.(a) Entry Substrate Time (min) Conv. % ee %
1 Ph-CO-Me 30 90 83 2 Ph-CO-Et(c) 50 84 93 3 (4-ClC6H4)-CO-Me(C) 50 93 70 (4-MeO-C6H4)-CO-4 Me(c) 50 78 81 1 -acetonaphthone (d) 50 93 95 6 Ph-CO-'Pr(`) 50 89 91 (a In the N2 glovebox, the iron complex (ii) (2.0 mg, 0.0014 mmol), KOtBu (1.3 mg, 0.0114 mmol) and ketone (2.2 mmol) were separately dissolved in the 5 mL

of 2-propanol, each. The resulting solutions were added to a vial charged with a stirring bar in the order: substrate, catalyst followed by base. The samples of the reaction mixture were analyzed by GC. (b) in 15 mL isopropanol with S/C/B
2000/1/8. (c) in 12 mL isopropanol. (d) in 14 mL isopropanol.

[0001341 The enantiopure complex trans-[Fe(NCMe)(CO)(9)](BF4)2 (iii), wherein 9 is as defined above:

-N N-/ PPh2 Ph2P

has also been prepared. This complex is inactive for catalytic hydrogenation directly from H2 gas but is useful for the asymmetric transfer hydrogenation of prochiral ketones and is useful for the transfer hydrogenation of ketones and imines. Complex (iii) has been crystallized as the BF4 (see Example 4) and the BPh4 salt and characterized by elemental analyses, NMR, IR, MS and single crystal X-ray diffraction. The (S,S)-enantiomer of complex (iii) has also been prepared and characterized. The enantiopure complex trans-[Fe(NCMe)(CNtBu)(9)](BF4)2 (iv) has also been prepared and characterized (see Example 5).
Me C
I (BF4)2 Fe P /
Ph2 ~2 Ph2 /

(iii) L2 = CO, * = R configuration L2 = tBuNC, * = R configuration Table 3. Transfer hydrogenation of ketones and imines from 2-propanol catalyzed by (iii) and KOtBu (S/C/B = 200/1/8) at 22 C.[al Time Conv. e.e. TOF
Entry Substrate (h) (%) (%) (h71) 1 Ph-CO-Me 0.4 95 29 (S) 907 21 j Ph-CO-Me 0.7 33 39 (S) 93 3 Ph-CO-Me 0.4 95 33 (S) 454 4 (2'-Cl-C6H4)-CO-Me 0.2 >99 18 (S) 995 (3'-Cl-C6H4)-CO-Me 0.4 99 24 (S) 495 6 (4'-C1-C6H4)-CO-Me 0.2 94 26 (S) 938 7 (4'-Br-C6H4)-CO-Me 0.2 93 33 (S) 930 8 (4'-Me-C6H4)-CO-Me 0.6 86 33 (S) 279 9 (4'-OMe-C6H4)-CO-Me 0.5 69 23 (S) 260 Ph-CO-Et 3.6 95 61(S) 26 11 C10H7-CO-Me [d] 0.3 94 25 (S) 564 12 Ph-CO-Ph 0.4 94 - 470 13 Ph-(CH2)2-CO-Me 0.6 100 29 (S) 315 14 Ph-CHO 2.4 94 - 77 Ph-CH=N-Ph 17 100 - 12 16 Ph-CMe=N-Ph 17 <5 - -17 Cyclohexanone 17 0 - -[0001351 a In an Ar or N2 glovebox at 22 C, the iron complex (5 mg, 0.005 mmol, [Cat] = 1.04 mM), KOtBu (5mg, 0.045 mmol) and the substrate (200 equiv) were stirred in 5 mL of 2-propanol. The conversion and enantiomeric excess of the products were determined by NMR spectroscopy and GC. [b1 S:C:B = 400:1:8, [Cat] = 0.1 mM, 10 mL iPrOH. [(] S:C:B = 200:1:2, [Cat] = 0.1 mM, 5 mL iPrOH.
[d] C10H7-CO-Me = 2-acetonaphthone. [e] TOF = turn over frequencies.

[0001361 As can be seen from Table 3, the electronic properties of the substituents on the phenyl ring of the ketone changed the reduction rate but had less effect on the enantioselectivity (18-33%). An acetophenone substituted in the para position by an electron releasing group, such as 4'-methyl and 4'-methoxy, is reduced more slowly than acetophenone (entries 3, 8 and 9). The chloro substituted acetophenones are all reduced faster, especially for the ortho position (entries 3-7). This trend is opposite to the generally observed trend for Noyori's transfer hydrogenation catalysts in which an ortho-CI substitution decreases the rate of the reduction (S. Hashiguchi, A. Fujii, J. Takehara, T. Ikariya, R.
Noyori, J.
Am. Chem. Soc. 1995, 117, 7562). The catalyst (iii) with KOtBu is also efficient for the transfer hydrogenation of propiophenone, 2-acetonaphthone, benzophenone, benzylacetone, benzaldehyde and N-benzylideneaniline (entries 11-15). The hydrogenation of propiophenone gave 1-phenylpropanol in 61% e.e (S) (entry 10). The more difficult ketimine N-phenyl-(1-phenylethylidene)amine (Ph-CMe=N-Ph) was only partially reduced (< 5%) after 18 h under the same conditions (entry 16), while cyclohexanone was not hydrogenated (entry 17).
Transfer hydrogenation of unsaturated ketones was complicated by some reduction of the C=C double bond (Scheme 2).

Scheme 2. Transfer hydrogenation of unsaturated ketones.

~~`~~OH ~OH
Ph" v Me Ph" Me + Ph"^"Me S:C:B = 200:1:8.22 C, 23 h 18% 82%
e.e. = 45% (S) e.e. = 27% (S) [0001371 Complex (iv) is useful for the asymmetric transfer hydrogenation of ketones. Complex (iv) was used in the transfer hydrogenation of acetophenone, using the same reaction conditions as noted for complex (iii) (see [a] in Table 3 above). After 2.6 hours the conversion was 34% and the e.e. was 76% (S).

[0001381 The mechanism of the catalysis is uncertain. The tetradentate ligand complex may be hydrogenated in the reaction medium to produce the amine intermediate [FeH(CO){(R,R)-cyP2(NH)2}]+; however, such a hydride has not yet been synthesized or observed in the catalytic solution. Such a complex might be expected to transfer a hydride from iron and a proton from nitrogen to polar bonds in an outer sphere hydrogenation, the mechanism postulated for the related complexes [RuH2{(S,S)-cyP2(NH)2}][15] and [RuH2{PPh2(o-C6H4)CH2NHCMe2CMe2NHCH2(o-C6H4)PPh2}] (T. Li, R. Churlaud, A. J. Lough, K. Abdur-Rashid, R. H. Morris, Organometallics 2004, 23, 6239). Since there is poor chemoselectivity for the reduction of the C=O bond versus the C=C during the hydrogenation of trans-4-phenyl-3-buten-2-one, another mechanism might be involved.

[00013 91 During the transfer hydrogenation of acetophenone catalyzed by (iii) (entry 3, Table 3), the 31P{IH} NMR shows an AB pattern at 56 and 74 ppm (d, 2JP_p = 28 Hz) due to an, as yet, unidentified intermediate. There is also a singlet for the free ligand 9 (R,R)-cyP2N2, and some other minor, unassigned peaks at 29 and -12.3 ppm. For the reaction catalyzed by (iv), the AB pattern for the intermediate is observed at 54 and 58 ppm (d, 2JP_P = 31 Hz). This intermediate decomposes upon attempt to isolate it from the catalytic mixture.
Without being bound by theory, it is thought that it might be a complex such as [Fe(CO)(X){(R,R)-cyP2N2}](BF4), X = alkoxide or hydride, but further study is required.

[0001401 The observation of free PNNP ligand in the catalytic solution may suggest the formation of colloidal iron; however, there is evidence that the active catalyst is homogeneous instead of heterogeneous in that the reaction solutions are clear. The e.e. of the product alcohols are reproducible. There is no poisoning of catalysis by mercury when it is added during the reaction (C. A. Jaska, I.
Manners, J. Am. Chem. Soc. 2004, 126, 9776).

[0001411 As it follows from Table 2, TOF (turn over frequencies), TON
(turn over numbers) and enantioselectivity of the catalyst (ii) are much higher compared to the catalysts (iii) and (iv). At a certain moment of the reaction when equilibrium between product and a substrate is established, catalytic racemization of the product starts taking place. It is hard to propose a reliable mechanistic explanation for such behavior of the catalyst at this point of investigation, but the conditions of the reduction can be optimized, so the product can be obtained in high yields and enantiopurity. When a smaller amount of the base is used the rate of the reaction is lower and thus the time at which racemization is taking place can be defined. If the reaction is quenched by simple exposure to air at this point of the process, high enantioselectivity and yields of the reaction can be achieved.
Those conditions have a disadvantage: the overall rate of the reaction and TOF
are reduced. In order to reach high enantioselectivity and conversion of the process the substrate concentration was increased. That increased the time of the reaction enough to determine when the equilibrium is established without reduction of the TOF and product was obtained in good ee, conversion and excellent TOF and TON.

[0 001421 Yellow solutions of complex (iii) are stable to oxidation in air for at least one day. The 1H NMR spectrum of (iii) showed the presence of a singlet for the imine protons at 9.11 ppm while the 13C { 1H} NMR spectrum displayed a pseudo-triplet for the carbonyl carbon. The 1H NMR spectrum of complex (iv) has two distinct resonances for the imines protons. The 31P{1H} NMR spectra consist of AB patterns at ca. 51 and 48 ppm (2Jp p - 40 Hz) for (iii) and ca.
58 and 48 ppm (2Jp.p = 51 Hz) for (iv). The IR spectra of (iii) and (iv) proved valuable.
The carbonyl ligand of (iii) absorbs at 2000 cm 1. Complex (iv) has absorptions at 2151 and 2173 cm1 for the tBuNC and MeCN ligands.

[0001431 Similarly, the enantiopure complex (v) is useful for asymmetric transfer hydrogenation of prochiral ketones and imines and is useful for the transfer hydrogenation of ketones and imines. Complex (v) has been crystallized as the BF4 salt (see Example 7) and characterized by elemental analyses, NMR, IR, MS. The (S,S)-enantiomer of complex (v) has also been prepared and characterized including a single crystal X-ray diffraction study.

Ph O Phi (BF4)2 P.Fe P\ / \
Ph Ph N Ph Ph C
(v) Table 4. Transfer hydrogenation of ketones from 2-propanol (6 mL) catalyzed by (v) and KOtBu (S/C/B = 600/1/8 unless specified) at 24 C under N2.(a) Time Conv. e.e.
Entry Substrate (min) (%) (%) 1 Ph-CO-Me 30 71 63 (S) 2 Ph-CO-Et 30 75 70 (S) 3 Ph-CO-'Pr 30 58 94 (S) 4 Ph-CO-'Bu b 15 93 96 (S) (2'-Cl-C6H4)-CO-Me 30 93 29 (S) 6 (3'-Cl-C6H4)-CO-Me 30 68 45 (S) 7 (4'-Cl-C6H4)-CO-Me 30 81 38 (S) 8 3-C10H7-CO-Me 30 61 52 (S) 9 2- C1oH7-CO-Me 30 73 61(S) Ph-(CH2)2-CO-Me 15 91 57 (S) 11 Me-CO-'Pr 15 63 12 (S) [0001441 (a )To a mixture of (v) (0.005 mmol) and KOtBu (0.04 mmol) was added a solution of ketone in 6 ml of iPrOH; (b) S/C/B = 200/1/8 [0001451 Other A groups of formula (1) can be envisaged such as the ferrocenyl substituent shown as part of compound 11.

[0001461 The above complexes can be prepared using an efficient, economical, template synthesis utilizing air stable phosphinoaldehyde precursor.
The synthesis of (I) is shown schematically as follows:

1) McOH R6 R7 1 m+
OH 2+ 2) Fez+ R5 RB
Ri2P ,A 'f--R 3) Strong base * * R4 R4- PR- 4) L', L2 ,N,' NzL-( i 2 Fe A
HO R5 2 P.
R" R' ' L \
M 5) R1 R' R' R' (VI) (I) [0001471 It is well known that in the process of hydrogenation or transfer hydrogenation, imine groups in the catalyst structure can be reduced to amine groups. These amine-containing catalysts, when they are soluble, are also active catalysts for the transfer hydrogenation of ketones under the same conditions as described for the imine catalysts described here.

[0001481 In one embodiment, there is provided a process for the preparation of a hexa-coordinate iron (II) complex of formula (I), the process comprising reacting a phosphinaldehyde precursor of formula (V):

OH 2+
R12P. -fLR4 R4-.AIPR12 HO

(V) wherein [0001491 each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R' groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R' groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

[000150] A is R3 ';
n [0001511 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

(0001521 each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

[0001531 with a diamine of formula (VI):
Rs R7 R6 *R8 (VI) wherein [0001541 each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from and (III \

[0001551 each of which may be optionally substituted with one or more substituents selected from the group consisting of Cl-C8 alkyl, C1-C8 alkoxy, and halogen atoms;

(0001561 in the presence of [0001571 an iron (II) salt;
[0001581 a ligand selected from the group consisting of CH3CN; pyridine and derivatives thereof; and imidazole and derivatives thereof; and (0001591 a strong base;
[0001601 to form the compound of formula (I) R6 R7 m+

* 4 T P, I % I\

(I) [0001611 wherein A, R1-R8, and n are as defined above, [000162] m is +2, [0001631 L' and L2 are both CH3CN; pyridine or a derivative thereof; or imidazole or a derivative thereof;
[0001641 and adding at least one counter ion to counterbalance the charge of the compound of formula (I).

[0001651 In one embodiment, the at least one counter ion is selected from BF4 ; PF6 ; SbF6 ; C104-; CH3SO3-; CF3SO3 ; C6H5SO3 ; p-CH3C6H4SO3 ; FeC142-, FeBr42-, B(R*)4, wherein R* is selected from phenyl, C6H3(CF3)2 and C6F5i halides; pseudohalides; C1-C8 alkoxides; and aryloxides. In another embodiment, the at least one counter ion is BF4 In another embodiment, the at least one counter ion is BPh4.

[0001661 In another embodiment, the compound of formula (I), wherein L1 and L2 are both CH3CN, pyridine or a derivative thereof, or imidazole or a derivative thereof, is further reacted with CO; hydride; halide ion; NCR, CNR
or OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbRcN wherein Ra, Rb, and R are independently selected from the group consisting of H and C1-C2 alkyl; or R (CO)R" wherein R and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl, to produce a compound of formula (VIIIa):

R5 R6 R7 R8 m+

* * a RY,,, 1 `N~ R
A, F2,~

(VIIIa) wherein A, R1-R8, and n are as defined for formula (I), [000167] L1 is CH3CN; pyridine or a derivative thereof; or imidazole or a derivative thereof; and [0001681 L2, is selected from the group consisting of CO; hydride; halide ion; NCR, CNR or OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR N wherein Ra, Rb, and Rc are independently selected from the group consisting of H and C1-C2 alkyl; or R (CO)Rd wherein R and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl, and m is +l or +2.

[0001691 In another embodiment, there is provided a process for the preparation of a hexa-coordinate iron (II) complex, the process comprising reacting a phosphinaldehyde precursor of formula (V):

OH 2+
R12P- `~R4 Ra-PR12 HO A
(V) wherein [00017 01 each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

AisR3 wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;
[000171] each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

with a diamine of formula (VI):

Rs R7 (VI) wherein [0001721 each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from * * , and [00017 31 each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
[0001741 in the presence of.
[000175] an iron (II) salt;
[00017 61 a ligand selected from the group consisting of CH3CN; pyridine and derivatives thereof; and imidazole and derivatives thereof; and [0001771 a strong base;
[0001781 and further reacting the reaction product of the foregoing steps with CO to produce a compound of formula (VIIIa):

R5 R6 R7 R8 m+
** 4 RY L ~' 1 '%N~
A- / i 2No o (VIIIa) [0001.7 91 wherein A, R'-R8, and n are as defined above, L1 is CO, L2is Br, and m is +1;

[0001801 and adding a counter ion to counterbalance the charge of the compound of formula (VIIIa).

[000181] The synthesis is conducted in an atmosphere of N2 (1 atm) or Ar (1 atm) or another suitable gas to prevent reaction with atmospheric oxygen.
[0001821 The concentration of the dimer V for use in forming the complexes disclosed herein can range from 0.5 M to 0.0005 M with a preferred concentration of 0.03M. The concentration of the diamine for use in forming the complexes disclosed herein can range from 0.5 M to 0.0005 M with a preferred concentration of 0.03M.

[0001831 Suitable iron (II) salts for use in forming the complexes disclosed herein include [Fe(H2O)6]2+ with counterions as noted herein, namely, Fe(BF4)2;
Fe(PF6)2; Fe(SbF6)2; Fe(C1O4)2i Fe(MeSO3)2i Fe(CF3SO3)2; Fe(C6H5SO3)2i Fe(p-CH3C6H4SO3)2; FeC142 FeBr42-; Fe[B(R*)4]2, wherein R` is selected from phenyl, C6H3(CF3)2 and C6F5; FeX2 wherein X is a halide or pseudohalide; Fe[O(C1-C8 alkyl)]2; FeSO4; Fe(N03)2; and Fe[R C(O)O]2, Wherein R** is CI-C3 alkyl, CF3, or phenyl, and hydrates thereof. The preferred range of iron concentrations for the template synthesis of complex II is 1 M to 0.001 M with a preferred concentration of 0.05 M

10001841 Suitable strong bases for use in forming the complexes disclosed herein include alkoxides, such as NaOMe, DBU, a phosphazene, or an alkaline or alkaline-earth metal carbonate salt, carboxylate salt, alkoxide salt or hydroxide salt. In one embodiment, the strong base may be MOR***, wherein M is an alkaline metal selected from Na and K, and R*** is C1-C4 alkyl. The preferred base to iron ratio is 1.3:1.

[0001851 Suitable solvents for forming the complexes disclosed herein include MeOH, EtOH, PrOH, iPrOH, BuOH, CH3CN, EtCN, pyridine, picoline, imidazole, methylimidazole. The preferred solvents are alcoholic solvents, such as MeOH. The preferred total volume of the solvent in the synthesis ranges from 1 mL to 20,000 mL with a preferred volume of 10 mL.

[0001861 The temperature for the template synthesis can range between 0 and 120 C with the preferred temperature being between 20 C and 40 C.
[0001871 The catalysts disclosed herein comprising a compound of formula (I) and with L' = L2 = MeCN are surprisingly active and selective for the hydrogenation, by use of hydrogen gas, of ketones to produce valuable chiral and non-chiral alcohols in the presence of a base and an appropriate solvent. The use of complex (i) provides a particularly active and usefully enantioselective catalyst system.

[0001881 The hydrogenation reaction involving a catalyst disclosed herein may or may not require solvent. When the use of the solvent is preferred for practical reasons, any solvent can be utilized for better performance of the catalyst. Non-limiting examples include primary, secondary and tertiary alcohols with hydrocarbon skeleton containing 2-15 carbons or aromatic solvents or ethers or hydrocarbon solvents.

(0001891 In the solvent, the catalyst can be used at concentrations of 0.001 mM to 0.1 mM while the substrate ketone or imine can be used in concentrations of 2 mM to 10 M. The pressure of hydrogen gas can range from 0.5 atm to 100 atm with a preferred pressure of 10 atm. Preferred concentrations of catalyst and substrate are 0.8 mM and 0.16 M, respectively, with a ketone to catalyst ratio of 200:1.

[0001901 In another embodiment, the phosphinaldehyde precursor is:
Ph2,,P~I OH
HO. v PPh2 the diamine is:
Ph Ph and the product is a compound of formula (I) having the structure:
Ph\ NC Ph 3 2+
r 4 CN~ Fe P.

Ph2 (III).
[0001911 In one embodiment, the chiral carbon atoms denoted by asterisks in (III) above both have an R configuration. In another embodiment, these chiral carbon atoms both have an S configuration.

All [0001921 The processes outlined herein generates a catalyst with sections derived from the precursor diamine (VI) and phosphine (V) precursor building blocks with the iron ion acting as a template to orient the precursors to ensure a high yield of the compound of formula (I). The sections are shown in structure (VII) below:

diamine R6 R a '+
R
R' R IIIL' i `0 'R
ASP L2 p R~ R~ R, phosphine phosphine (VII) [0001931 This is an advantage since different catalysts can be rapidly synthesized from a phosphine precursor and a diamine precursor with a variety of substitutents, providing flexibility to appropriately optimize manufacturing costs and end product quality specifications, such as a high enantiomeric excess.
The methods disclosed herein allow for tuning of the coordinating ligand to obtain the easy introduction of chiral elements such as enantiomerically pure diamines into the catalyst because of the modular nature of the coordinating ligand. As a consequence, the iron (II) complex with PNNP ligand is easily modified by introducing substituents to produce a catalyst structure capable of interaction with a substrate and ensuring selectivity. Where both enantiomers of these diamines are available, both enantiomers of an iron catalyst can be easily prepared to hydrogenate a substrate to either enantiomer of the target molecule.

(0001941 The phosphine-aldehyde precursors (V) are prepared by methods known in the art from commercially available or readily prepared phosphine starting materials PHR12 or PC1R12 and compounds XCR2R3Y where X is a halide or tosylate or other good leaving group known in the art and Y is a formyl group -CHO or a protected formyl group -CH(OR)2. In addition, a new method for the synthesis of phosphine-aldehyde precursors of formula (XIII) is outlined below. The diamines NH2CRSR6CR7R8NH2 are available from commercial sources.

[0001951 A most interesting catalyst has the discrete structure (i), shown above (also see Example 1). The chiral ligand can have an (R, R) or (S, S) configuration. To counterbalance the 2+ charge in the metal complex salt, anions such as BF4, PF6, SbF6, FeC142', FeBr42 tetraarylborates where the aryl is Ph, C6H3(CF3)2 or C6F5, or halides or pseudohalides or alkoxides and others noted above may be used.

[0001961 Catalysts of structure (i), for example the tetraphenylborate salt, are prepared in a similar fashion to that of other iron complexes reported by Mikhailine et al. (Mikhailine et al. "Template Syntheses of Iron(II) Complexes Containing Chiral P-N-N-P and P-N-N Ligands," Inorg. Chem. 47 (2008), pp 6587 - 6589) by the template reaction of the phosphonium salt shown below with (R,R)-dpen as described in Example 1: (S,S)-dpen can alternatively be used to generate the other enantiomer of (i).
Scheme 3 1) McOH Me Ph2P OH 2) [Fe(H20)6]2+ Ph N Ph 3) NaOMe HOLPPh2 (Br )2 _N**,, .=N., (BPh4)2 4) MeCN CPS Fe `P~

5) (R,R)- or Ph2 Ph2 (S,S)- dpen C (S,S)-enantiome Me or Me Ph,, N Ph '= ,N (BPh4)2 CPS Fe `P
Ph2 I Ph2 C (R,R)-enantiom Me [0001971 The complexes are precipitated as the BPh4' salts in high yield and characterized by NMR, electrospray ionization mass spectrometry, and elemental analysis. The detailed procedure of the complex (i) preparation is described as Example 1.

[0003.981 The reaction of complex I where Lt = L2 = acetonitrile or another nitrogen donor ligand such as imidazole or pyridine with carbon monoxide yields the monocarbonyl catalysts of formula (VIII).

R6 R7 m+
R S Rg * 4 R ~N,~ I~ ~NR
P~C'N A
P
R' R' R'' R' (Vi) (000199] For example when complex (i) in acetone is treated with 5 atm CO, the monocarbonyl complex (ii) is formed (see Example 2). When the complex trans-[Fe(NCMe)2(9)](BF4)2 (Sui-Seng et al., "Highly Efficient Catalyst Systems Using Iron Complexes with a Tetradentate PNNP Ligand for the Asymmetric Hydrogenation of Polar Bonds." Angew. Chem. Int. Ed. Engl. 47 (2008), pp. 940-943) in acetone is reacted with 1 atm CO, the carbonyl complex trans-[Fe(NCMe)(CO)(9)](BF4)2 (iii) is formed (see Example 4). Similarly when [Fe(NCMe)2(9)](BF4)2 in acetone is reacted with tertiary-butylisocyanide, the complex [Fe(NCMe)(CNtBu)(9)](BF4)2 (iv) is formed (see Example 5). The reaction of complex (vi) (Mikhailine et al. "Template Syntheses of Iron(II) Complexes Containing Chiral P-N-N-P and P-N-N Ligands," Inorg. Chem. 47 (2008), pp 6587 - 6589) (Example 8) with CO produces the complex (vii;
Example 9).
Scheme 4 Me Co N
Fle N, BPhy~ _ CO N ~N, CPS !P~ : acetone CP2 1 P 2 [ BPh4] 2 Ph2 N Ph2 Ph N Ph Me Me (vi) (Vii) [0002001 If the compound of formula (I) is reacted with carbon monoxide prior to the addition of a counterion and isolation of the iron (II) complex, this yields the compounds of formula (VIIIa) R6 R7 1 m+

A Pi 12 A
,\P
R1 R1 R'Rl (VIIIa) [ 0 0 0 2 01 ] wherein A, R1-R8, and n are as defined for formula (I), L1 is CO, L2' is Br, and m is +1. A counter ion is then added to counterbalance the charge of the compound of formula (VIIIa). These iron (II) complexes have been found to be catalytically active.

[0002021 Complex vi has less than optimum activity (< 5% conversion) for the hydrogenation of acetophenone at 35 C, 25 atm H2 with KOtBu in iPrOH, and is inactive for the transfer hydrogenation of ketones in basic isopropanol.

[0002031 Catalyst (vii) can be used for transfer hydrogenation. In the N2 glovebox, the iron complex (vii) (8.7 mg, 0.007 mmol), KOtBu (6.3 mg, 0.056 mmol) and acetophenone (168 mg, 1.4 mmol) were separately dissolved in the 3 mL of 2-propanol, each. The resulting solutions were added to a vial charged with a stirring bar in the order: substrate, catalyst followed by base and stirred at room temperature. The samples of the reaction mixture were analyzed by GC. The conversion was 92% after 75 minutes.

[0002041 Complex trans-[Fe(MeCN)2(6)] (BF4)2 (Example 10) wherein 6 is `N `
nN~
C / PPh2 Ph2P \ /

n = 2, was prepared and tested. For the hydrogenation of acetophenone with H2 (25 atm) with a catalyst to base to substrate ratio of 1:15:225 in isopropanol the conversion was 4% after 18 h. It was found to be inactive for the transfer hydrogenation of acetophenone in basic isopropanol under the standard conditions.

[0002051 The iron (II) complex trans-[Fe(MeCN)2(6)](BF4)2, can be reacted with CO to produce O (BF4)2 Ph Ph N Ph Ph C

(viii) (Example 11).

[0002061 Catalyst (viii) can be used for transfer hydrogenation. To a mixture of (viii) (0.005 mmol) and KOtBu (0.04 mmol) was added a solution of ketone in

6 ml of iPrOH. Catalyst (viii) was found to be highly active for the transformation of acetophenone to 1-phenylethanol at room temperature using a catalyst:base:substrate ratio of 1:8:600 (85% conversion after 60 min).

[0002071 The bis-acetonitrile complexes trans-[Fe(NCMe)2 (9) } ] [BF4]2, trans- [Fe(MeCN)2(6)](BF4)2,wherein 6 is ~N nN._.

PPh2 Ph2P \ / / -\ /
where n - 2 and trans-[Fe(NCMe)2 {(R,R)-PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2}][BF4]2 were prepared by reaction of the known PNNP ligands 6 (Jeffery, J. C.; Rauchfuss, T. B.; Tucker, P. A.
Inorg.
Chem. 1980, 19, 3306-3316) 9, and PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2 (J.-X. Gao et al. Chirality 2000, 12, 383) with iron salts such as [Fe(OH2)6](BF4)2 in acetonitrile as described in the examples below.

[0002081 The iron complexes trans-[Fe(NCMe)(CO)(6)j[BF4], (RR)- or (S,S)-trans-[Fe(NCMe)(CO){9)}][BF4]2 and (R,R)- or (S,S)- trans-[Fe(NCMe)(CO)(PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2)][BF4]2 were obtained as orange solids in good yields when the corresponding bis-acetonitrile compounds just mentioned were stirred under a CO atmosphere in acetone. The new compounds are fairly air stable, both as a solid and in solution. They are soluble in acetonitrile and methylenechloride, poorly soluble in acetone, chloroform, 2-propanol and insoluble in tetrahydrofuran, ether and hydrocarbons.
The new compounds were characterized by 1H and 13C and 31P NMR techniques, elemental analysis, mass spectroscopy, IR and the solid state structures were confirmed by X-ray crystallography. The 31P{'H} NMR spectrum of trans-[Fe(NCMe)(CO)(6)][BF4]2 shows a singlet while those for (R,R)- or (S,S)-trans-[Fe(NCMe)(CO)(9)}][BF4]2 and (RR)- or (S,S)- trans-[Fe(NCMe)(CO)(PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2)][BF4]2 show two doublets. Mass spectra (ESI) show the cationic fragment without the acetonitrile and carbonyl ligands.

[0002091 In one embodiment, there is provided a process for preparing an alcoholic compound wherein said process comprises a step of preparing the alcoholic compound by reducing a ketone or aldehyde with the reaction of hydrogen or a compound donating hydrogen in the presence of a hexa-coordinate iron (II) complex of formula (I), with the proviso that the ketone is not an unsubstituted cycloalkanone.

10002101 As can be seen from Table 3, no conversion was observed for the transfer hydrogenation of cyclohexanone catalyzed by (iii). However, it is envisioned that cyclic ketones having substituents such as aromatic groups may be better substrates.

(0002111 In another embodiment, the hexa-coordinate iron (II) complex comprises a compound of formula (I) having the structure:

Ph NCPh 3 2+
"ON
N,,, CPIFe P) Ph2l Ph2 (III).
(0002121 In another embodiment, the chiral carbons atoms denoted by asterisks both have an R configuration. In another embodiment, the chiral carbons atoms denoted by asterisks both have an S configuration, In another embodiment, the reaction uses hydrogen.

[0002131 In yet another embodiment, the substrate is a ketone. In another embodiment, the ketone is an aromatic ketone. In yet another embodiment, the ketone is prochiral.

[0002141 In another embodiment, there is provided a process for preparing an amine compound wherein said process comprises a step of preparing the amine compound by reducing an imine with the reaction of hydrogen or a compound donating hydrogen in the presence of a hexa-coordinate iron (II) complex of formula (I). In another embodiment, the hexa-coordinate iron (II) complex comprises a compound of formula (I) having the structure:
Me N 1 (BF4)2 _N_ FIe /
ph2 CO Ph2 [0002151 In another embodiment, the chiral carbons atoms denoted by asterisks both have an R configuration. In another embodiment, the chiral carbons atoms denoted by asterisks both have an S configuration. In another embodiment, the reaction uses a compound donating hydrogen. In another embodiment, the imine is not prochiral.

[0002161 The catalysts I disclosed herein can reduce aldehydes, ketones and imines with general structure (IX):
Q
R."k R"
(IX) (0002171 where the R', R" symbols, taken separately, represent simultaneously or independently a hydrogen atom, a linear or branched alkyl or alkenyl chain containing 1-8 carbon atoms, possibly substituted, a cycloalkyl radical or an aryl group, possibly substituted. The symbol Q represents simultaneously or independently an oxygen atom or NR"' group, where R"' symbol represent simultaneously or independently a hydrogen atom, a linear or branched alkyl or alkenyl chain containing 1-8 carbon atoms, possibly substituted, a cycloalkyl radical or an aryl group, possibly substituted. Possible substituents include alkyl groups (such as Cl-C8 alkyl), aryl groups, halogens, and alkoxy groups.

[0002181 The reduction of ketones and imines with general structure (IX) produce products, namely alcohols and amines, respectively with general structure (X). When the correct asymmetric hydrogenation or transfer hydrogenation catalyst I is applied, the products are obtained in one enantiomeric form. For example the use of complex (i) in asymmetric hydrogenation gives the S-alcohol in high e.e. while the use of complex (ii) or (v) in asymmetric transfer hydrogenation gives the S-alcohol in high e.e. The correct catalyst I might also be used for other catalytic asymmetric reactions such as the transfer of hydrogen from a hydrogen donor such as isopropanol or ethanol to a ketone or imine. The use of the catalysts disclosed herein for addition of a hydrosilane to a ketone or imine, an asymmetric Michael addition of donor to an acceptor, an asymmetric Diels-Alder reaction of an olefin to a diene or an asymmetric cyclopropanation reaction may also be possible.

H
IQ
R"<R"
(X) [0 002191 The catalysts disclosed herein comprising a compound of formula (I) and with L' = L2 = MeCN are surprisingly active and selective for the hydrogenation, by use of hydrogen gas, of ketones to produce valuable chiral and non-chiral alcohols in the presence of a base and an appropriate solvent. The use of complex (i) provides a particularly active and usefully enantioselective catalyst system.

[0002203 The hydrogenation reaction involving a catalyst disclosed herein may or may not require solvent. When the use of the solvent is preferred for practical reasons, any solvent can be utilized for better performance of the catalyst. Non-limiting examples include primary, secondary and tertiary alcohols with hydrocarbon skeleton containing 2-15 carbons or aromatic solvents or ethers or hydrocarbon solvents.

[0002211 In the solvent, the catalyst can be used at concentrations of 0.001 mM to 0.1 mM while the substrate ketone or imine can be used in concentrations of 2 mM to 10 M. The pressure of hydrogen gas can range from 0.5 atm to 100 atm with a preferred pressure of 10 atm. Preferred concentrations of catalyst and substrate are 0.8 mM and 0.16 M, respectively, with a ketone to catalyst ratio of 200:1.

[0002221 The base in the hydrogenation process using H2 gas can be substrate (if it has a basic functionality) or a strong neutral base such as DBU or a phosphazene, or an alkaline or alkaline-earth metal carbonate salt, carboxylate salt, alkoxide salt or hydroxide salt. The base in the process can be used in a concentration of between one and fifty times the concentration of the catalyst concentration. The preferred base to catalyst ratio is 15.

(0002231 The temperature of the direct hydrogenation with hydrogen gas catalyzed by complexes comprising a compound of formula (I) and with L' = L2 =
MeCN can range between 0 and 120 C with the preferred temperature being 35 C.

[0002241 Catalysts such as (ii) are particularly active and selective for the asymmetric transfer hydrogenation of ketones to non racemic alcohols in basic isopropanol solvent or other alcohols or mixtures such as formic acid/triethylamine known in the art to transfer hydrogen. Similarly, complexes (iii), (iv) and (v) can also be used as catalysts for the asymmetric transfer hydrogenation of ketones and the transfer hydrogenation of certain imines. The catalysts (VIII) with the ligand L' = MeCN or another nitrile donor ligand and = CO are surprisingly active and selective for the reduction of ketones to non-racemic alcohols by transfer of hydrogen from basic isopropanol or other alcohols or mixtures such as formic acid/triethylamine known in the art to transfer hydrogen.

[0002251 The conditions for the transfer hydrogenation catalyzed by catalysts (ii), (iii), (iv), (v) and of the type (VIII) are surprising mild.
The preferred temperature is room temperature but a range of temperatures is possible from 0 and 150 C. The turnover numbers reported in the examples are unprecedented for non-PGM catalysts that operate at room temperature.

[0002261 The transfer hydrogenation catalysts (ii), (iii), (iv), (v) and of the type (VIII) can be used at concentrations of 0.001 mM to 1 mM while the substrate ketone or imine can be used in concentrations of 2 mM to 5 M.
Preferred concentrations of catalyst and substrate are 0.1 mM and 0.2 M, respectively, with a ketone to catalyst ratio of 1600:1 for catalyst (ii) and 200:1 for catalyst (iii) and 600:1 for catalyst (v) or in general a substrate to catalyst ratio of 500:1.

[0002271 The base in the transfer hydrogenation process can be substrate (if it has a basic functionality) or a strong neutral base such as DBU or a phosphazene, or an alkaline or alkaline-earth metal carbonate salt, carboxylate salt, alkoxide salt or hydroxide salt. The base in the process can be used in a concentration of between one and fifty times the concentration of the catalyst concentration. The preferred base to catalyst ratio is 8.

[0002281 A new method of synthesizing phosphonium dimers has been developed. It has been found that such phosphonium dimers can be synthesized by the direct reaction of an alkyl-substituted secondary phosphine with organic compounds containing both a protected aldehyde and a carbon-halogen bond according to the general reaction scheme shown below.
O."Re 1) X` Re in THE R, RI
v \/
2) H2O, heat P OH X2 HO
R1Ri [0002291 A process for preparing a phosphonium dimer of formula (XIII) is provided:

P

HO
RI/ P\ R1 (XIII) [0002301 wherein R' is selected from the group consisting of C 1-C8 alkyl, C1-C8 substituted alkyl, cycloalkyl, and substituted cycloalkyl, and X
is selected from the group consisting of Br and I, the process comprising:
reacting a compound of formula (XI):
HPR12 (XI) wherein R1 is as defined above;
with a compound of formula (XII):
0 ~Re X.,OyRe (ten wherein X is as defined above, and Re is C1-C8 alkyl, or the two Re can combine to form a C2-C3 linear alkyl diradical;
and heating the reaction product in the presence of water to form the phosphonium dimer of formula (XIII).

[0002311 R1 is an electron-donating alkyl substituent, and in one embodiment the two R' groups on each phosphorus atom may be different. Re may be, for example, Me, Et, Pr etc. or (Re)2 = -CH2CH2-.

[ 0 0 02 3 21 Cyclic phosphonium dimers V with A=CH2 and R4 = H and with R1 = cyclohexyl (Example 15) isopropyl (Example 21) or ethyl (Example 22) substituents at the phosphorus atoms were prepared in a new, direct reaction of the secondary phosphine with the protected bromoacetoaldehyde diethyl acetal (BrCH2CH(OEt)2) in THF, neat or in other organic solvents that dissolve the compounds to give an intermediate phosphonium salt that was then hydrolyzed.
The yields of the white solids are 80, 81 and 40%, respectively. The cyclohexyl and isopropyl compounds are air- and moisture-stable white solids that are soluble in methanol or/and water and insoluble in other common organic solvents.
They possess similar physical properties to that of the dimer with phenyl groups on phosphorus. The dimer with ethyl groups, on the other hand, adsorbs water on prolonged exposure to atmosphere, and is soluble only in water. However an aqueous solution of this compound is stable toward oxidation by molecular oxygen.

[0002331 The new dimers were fully characterized by NMR spectroscopy and X-ray diffraction experiments. These compound show two characteristic singlets in the 31P{1H} NMR spectra in the region between 11 and 40 ppm and a multiplet in the region between 5.3 and 6.2 ppm for the proton on the carbon with the hydroxyl group -CH(OH)-, a downfield shift of the aldehyde hydrogen resonance which is expected in the 9-10 ppm region. The two singlets observed in the 31P{1H} NMR arise from the rac and meso diastereomers.

[0002341 The invention will now be described in further detail by way of the following examples, wherein the temperatures are indicated in degrees centigrade and the abbreviations have the usual meaning in the art.

Examples General Considerations.
[0002351 All preparations and manipulations were carried out under an argon or nitrogen atmosphere using standard Schlenk, vacuum-line, and glove-box techniques. Dry, oxygen-free solvents were prepared by distillation from appropriate drying agents and employed throughout. The synthesis of the ligands (R,R)-cyP2N2 (9) and (R,R)-PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2 have been reported previously (J.-X. Gao, H. Zhang, X.-D. Yi, P.-P. Xu, C.-L. Tang, H.-L.
Wan, K.-R. Tsai, T. Ikariya, Chirality 2000, 12, 383). All other reagents used in the experiments were obtained from commercial sources and used as received.
The mass spectroscopy (ESI1, MeOH) and elemental analyses were performed at the University of Toronto, on sample handled under argon for the EA. Varian Gemini 400 MHz and 300 MHz spectrometers were employed for recording 'H
(400 MHz and 300 MHz), 13C{1H} (100 MHz and 75 MHz), and 31P{1H} (161 MHz and 121 MHz) NMR spectra at ambient temperature. The 'H and 13C NMR
spectra were referenced to solvent resonances, as follows: 7.26 and 77.16 ppm for CHC13 and CDC13, 1.94 and 1.24 ppm for CH3CN and CD3CN). The 3,P NMR
spectra were referenced to 85% H3PO4 (0 ppm). All infrared spectra were recorded on a Nicolet 550 Magna-IR spectrometer.

[0002361 The samples of hydrogenation reaction mixtures were analyzed by 'H NMR spectroscopy and GC using a Perkin Elmer Autosystem XL
chromatograph with a chiral column (CP chirasil-Dex CB 25 m x 2.5 mm).
Hydrogen was used as a mobile phase at a column pressure of 6 psi. The injector temperature was 250 C, and a FID temperature was 275 C. The retention times of the substrates are listed in Table 5.

[0002371 trans-4-phenyl-3 -buten-2-one: the GC analysis were conducted as above, except that for the GC conditions the oven temperature was 140 C. The retention times were trans-4-phenyl-3-buten-2-one 7.8 min, I-4-phenyl-2-butanol 11.1 min, (S)-4-phenyl-2-butanol 11.4 min, trans-4-phenyl-3-buten-2-one 13.4 min, trans-(R)-4-phenyl-3-buten-2-ol 15.9 min, trans-(S)-4-phenyl-3-buten-2-ol 16.2 min. The product was also identified by 1H NMR spectroscopy and the data obtained matches literature values.

[0002381 N-Benzylideneaniline and benzophenone: the conversion of the product was determined by 1 H NMR spectroscopy and the data matches those of the commercial samples.

[0002391 General procedure for the iron catalyzed H2-hydrogenation of polar bonds: In an Ar or N2 glovebox, the iron complex (8 mg, 0.008 mmol) was suspended in 2 mL of 2-propanol and acetophenone (225 equiv) in 1 mL of 2-propanol. The solution of base was prepared by dissolution of KOtBu (15 equiv) in 2 mL of 2-propanol. The solution containing the substrate and then the one with base, followed by the suspension of catalyst were injected into a 50 cm3 Parr hydrogenator reactor filled with hydrogen at the desired pressure and temperature, maintained by use of a Fischer Scientific Isotemp 1016D water bath.

[0002401 The procedures for the iron catalyzed transfer hydrogenation of polar bonds are found in the footnotes of the Tables above.

Table 5.
[000241] GC analytical data for the reduced substrates (ts = retention time of substrate; tl, t2 = retention times of the products) Substrate Oven Temp. is (min) t1 (min) t2 (min) ( C) Ph-CO-Me 130 5.0 8.5 9.1 (2'-Cl-C6H4)-CO-Me 145 4.7 10.0 11.7 (3'-Cl-C6H4)-CO-Me 130 7.8 16.6 17.7 (4'-Cl-C6H4)-CO-Me 145 5.9 11.1 12.0 (4'-Br-C6H4)-CO-Me 155 6.5 11.4 12.1 (4'-Me-C6H4)-CO-Me 125 6.5 9.6 10.4 (4'-OMe-C6H4)-CO-Me 130 15.6 21.8 23.2 Ph-CO-Et 105 18.4 48.5 51.5 C10H7-CO-Me [a] 150 21.8 35.7 37.5 C10H7-CO-Me[h] 140 24.1 63.6 73.9 Ph-CHO 130 3.9 5.9 -Ph-CO-iPr 114 11.0 37.2 37.8 Ph-CH2-CH2-CO-Me 135 7.9 11.8 12.6 Ph-CO-tBu 140 5.9 11.6 12.2 CH3-CO-CH-(CH3)2 60 2.9 8.2 8.5 [a] 2-acetonaphthone. [b] 1-acetonaphthone Preparation of the catalyst (R, R) -[Fe(Ph2PCH2CH NCH(Ph)CH(Ph)N=CHCH2PPh2)(CH3CN)2][BPh4]2i (i) Me Ph,, N Ph CP~Fe ~ (BPh4)2 P
Ph2 N Ph2 C
Me Synthesis of the diphenylphosphino-acetaldehyde hydrobromide dimer:
[000242] The procedure for the synthesis of the diphenylphosphino-acetaldehyde hydrobromide dimer has been previously reported by Matt et al.
(Matt, D.; Ziessel, R.; De Cian, A.; Fischer, J. New J. Chem. 1996, 20, 1257-1263) and was used in this study with modifications. Potassium hydride (413 mg, 10.3 mmol) was partially dissolved in 10 mL of dry THE Diphenylphosphine (1.60 g, 8.58 mmol) was added to the resulting mixture to give a purple solution.
After 30 min the solution was cooled to -78 C and bromoacetaldehyde diethyl acetal (1.691 g, 8.58 mmol) was added over the course of 15 min. The mixture was brought to room temperature to give a yellow solution. A diluted hydrobromic acid (10 mL, 1.17 mol_L-1) were added and the mixture was heated at 40 C overnight. The solvent volume was reduced by one half. The white precipitate was recovered by filtration and washed with 20 mL of water and 20 mL cyclohexane:ethyl acetate (1:1 by volume). Drying in vacuo yielded 4 (2.51 g, 4.06 mmol) as a white powder. Analytical data were the same as those that have been reported by Matt et al.

Synthesis of the catalyst (R, R)-[Fe(Ph2PCH2CH=NCH(Ph)CH(Ph)N=CHCH2PPh2)(CH3CN)2] [BPh4]2, (i) [0002431 The diphenylphosphino-acetaldehyde hydrobromide dimer (200 mg, 0.324 mmol) was completely dissolved in MeOH (6 mL). [Fe(H20)6][BF4]2 (164 mg, 0.485 mmol) was added to the reaction mixture. NaOMe (34.9 mg, 0.647 mmol) was added as a MeOH (1 mL) solution and the color of the solution changed from colorless to clear yellow. After 10 min of stirring, 1 mL of acetonitrile was added. To this solution was added, over the course of 20 min, a solution of (1R,2R)-(+)-1,2-diphenylethylenediamine (R,R-dpen, 69 mg, 0.323 mmol) in 0.5 mL of acetonitrile. The solution changed color to purple after the addition. After 20 h the resulting solution was added to a solution of NaBPh4 (250 mg, 0.658 mmol) in 1 mL of MeOH to cause the formation of the precipitate. A
pink solid was recovered by filtration and dried under vacuum. Yield of (i):
83%
(380 mg); 1H NMR (400 MHz, CD3CN) 6: 1.54 (s, 6H, CH3CN), 3.95-4.15 (m, 2H, HCP), 4.26-4.38 (m, 2H, HCP), 5.43 (m, 2H, HC-N), 6.80-7.75 (m, 70H, ArH), 8.10-8.27 (m, 2H, HC=N). 31P {H} NMR (121 MHz; CD3CN): 72.63 ppm (s). Anal. Calcd for C94H84N4P2FeB2: C, 80.14; H, 6.01; N, 3.98. Found: C, 79.20;
H, 6.08; N, 4.65. MS (ESI) Calcd for [C46H44N4P2Fe-2(CH3CN)]2+: 344.3 m/z.
Found: 344.1 m/z. MS (ESI") Calcd for [B(Ph)4]": 319.2 m/z. Found: 319.2 m/z.

Preparation of the catalyst (R, R)-[Fe(Ph2PCH2CH=NCH(Ph)CH(Ph)N=CHCH2PPh2)(CH3CN)(CO)] [BPh4]2, (ii) CO
Ph,, Ph CP Fe P~ [ BPh4 12 Ph2 N Ph2 C
Me [0002441 The tetraphenylborate salt of the bisacetonitrile complex (i) (200 mg, 0.142 mmol) was dissolved in (10 mL) of degassed acetone under inert atmosphere. Resulting solution was placed in the CO high pressure reactor and was stirred under 5 atmosphere of CO for 12 hours at room temperature. Solvent was evaporated under reduced pressure and resulting solid was washed with diethyl ether (5 mL) three times. Yellow solid was dried under vacuum. Yield of (ii): 75 % (149 mg); 1H NMR (400 MHz, acetone-d6) S: 1.54 (s, 3H, CH3CN), 4.42-4.57 (m, 2H, HC-N), 5.58-5.76 (m, 4H, HCP), 6.80-7.75 (m, 70H, ArH), 8.14-8.23 (m, 2H, HC=N); 31P {'H} NMR (121 MHz; acetone-d6): 69.3 ppm (d, Jp-p=30Hz); 65.7 ppm (d, Jp.p 30Hz); MS (ESI) Calcd for [C46H44N4P2Fe-(CO+CH3CN)]2+: 344.3 m/z. Found: 344.1 m/z. MS (ESI-) Calcd for [B(Ph)4]":
319.2 m/z. Found: 319.2 m/z , IR (KBr) 2294 cm 1 (vC1, MeCN), 2001 cm 1 (vCO).

Preparation of the complex [Fe(NCMe)2(9)}][BF4]2 Me IICI (BF4)2 N
Fe /-Ph2~ I ' Ph2 N
u C
Me R configuration [0002451 A suspension of (R,R)-cyP2N2 (9) (317 mg, 0.48 mmol) in 7 mL of MeCN was added dropwise to a solution of [Fe(H2O)6][BF4]2 (162 mg, 0.48 mmol) in MeCN (12 mL). After stirring for 20 min at room temperature, the red solution was concentrated to 1 mL and 10 mL of Et2O were added. A red-orange powder precipitated and was isolated by filtration and washed with Et2O.
Recrystallization of [Fe(NCMe)2{9}][BF4]2 from a CHC13/ether solution gave the product (435 mg, 92% yield). A CDC13 solution in a NMR tube yielded red crystals suitable for X-ray diffraction studies and elemental analysis. 1H NMR
(400 MHz, CDC13) S= 9.26 (s, HC=N), 8.06-6.63 (m, ArH), 3.68 (s, CH), 2.70-2.13 (m, CH2), 1.75 (s, CH3CN). 13C{1H} NMR (100 MHz, CDC13) 5:172.45 (s, HC=N), 138.66-124.84 (m, Cazo,,,atic and C=N), 71.52, 66.05 (s, CH), 31.54, 29.26, 24.16, 22.82 (s, CH2), 1.22 (s, CH3CN). 31P{1H} NMR (161 MHz, CDC13) S:
53.4 (s) ppm. 31P{1H} NMR (161 MHz, CD3CN) S: 52.6 (s) ppm. Anal. Calcd.
for C48H46N4B2F8P2Fe1Ø5CHC13: C, 56.55; H, 4.55; N, 5.44. Found: C, 56.45;
H, 4.91; N, 5.04. IR (KBr) 2284 cm1 (vC mil, MeCN). MS (EST}, MeOH) for [Fe(9)]2+ (m/z = 357.1).

Preparation of the catalyst [Fe(NCMe)(CO){9}][BF4]2, (iii).

Me C
III
N (BF4)2 Fe Ph Ph R configuration [0002461 Method A. A solution of [Fe(MeCN)2 { 9 } ] [BF4]2 (Example 3, 200 mg, 0.21 mmol) in acetone (10 mL) was stirred under 2 atm CO overnight at room temperature. The resulting orange-yellow solution was evaporated to dryness to give an orange powder (quantitative yield).

[0002471 Method B. A solution of [Fe(MeCN)2 {9} ] [BF4]2 (Example 3, 160 mg, 0.17 mmol) in CHC13 (3 mL) was refluxed under 2 atm CO for 48 hours. The resulting orange-yellow solution was evaporated to dryness to give an orange powder (iii) (quantitative yield).

[000248] 1HNMR (400 MHz, CDC13) 5: 9.11 (s, CH=N), 8.21-6.35 (m, ArH), 3.53-3.32 (m, CH), 2.77-1.21 (m, CH2), 1.75 (s, CH3CN). 13C{1H} NMR
(100 MHz, CDC13) 6: 213.75 (t, 2Jc_p = 27.2 Hz, CO), 171.87 (d, 3Jc_p = 25.3 Hz, HC=N), 139.42-123.85 (m, Caromatic and C=N), 70.56, 65.99 (s, CH), 32.22, 30.89, 24.36, 23.71 (s, CH2), 1.03 (s, CH3CN). 31P{1H} NMR (161 MHz, CDC13) 5: 51.82 (d, 2JP_p = 40.6 Hz), 48.03 (d, 2JP_p = 40.6 Hz). Anal. Calcd. for C47H43N3OB2F8P2FeØ25CHC13: C, 57.49; H, 4.42; N, 4.26. Found: C, 57.36; H, 4.99; N, 4.10. IR (KBr) 2294 cm-1 (vC mil, MeCN), 1999 cm-1 (vCO). MS (ESI`1, MeOH) for [Fe{9 }]2+ (m/z = 357.1).

Preparation of the catalyst [Fe(NCMe)(CN`Bu){9}][BF4]2, (iv).

Me C
III
N 1 (BF4)2 c") _ I?N_ Fe Ph2 I `Ph N
tBu R configuration [000249] A solution of [Fe(MeCN)2{9}][BF4]2 (Example 3; 95 mg, 0.098 mmol) and tBuNC (22 LL, 0.196 mmol) in acetone (3 mL) was stirred for 2 h at room temperature. The resulting orange-yellow solution was evaporated to dryness to give an orange powder of (iv). (quantitative yield). 1H NMR
(400 MHz, CDC13) S: 9.27, 8.87 (s, CH=N), 8.30-6.55 (m, ArH), 3.71-1.58 (m, CH and CH2), 2.17 (s, CH3CN), 1.21 (s, (CH3)3CNC). 13C{1H} NMR (100 MHz, CDC13) 6: 173.47, 171.62 (s, HC=N), 139.60-125.38 (m, Caromatic, C=N and N=C), 75.8, 73.61 (s, CH), 32.38, 31.76, 24.76, 23.90 (s, CH2), 29.45 (s, (CH3)3CNC), 1.03 (s, CH3CN). 31P{1H} NMR (161 MHz, CDC13) 6: 58.22 (d, 2Jp.p = 51 Hz), 48.48 (d, 2JP_p = 51 Hz). IR (KBr) 2151, 2173 cm 1 (uC'1, MeCN and tBuNC).

Preparation of trans-[Fe(NCMe)2 {(R,R)-PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2} ] [BF4]2 A solution of (R,R)-PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2 (510 mg, 0.78 mmol) and [Fe(H2 O)6][BF4]2 (260 mg, 0.78 mmol) in MeCN (10 mL) was stirred for 1 h at ambient temperature. The solution was evaporated and the remaining red residue was washed with pentane. The analytically pure product was obtained after crystallization from MeCN/Et20 as dark red crystals (510 mg, 64%).
Recrystallization from a McCN/MeOH/Et2O solution yielded crystals suitable for X-ray diffraction studies. 1 H NMR (400 MHz, CD3CN): 9.32 (s, CH=N), 7.82-

7.21 (m, Ar-H), 6.94 (m, Ar-H), 6.85 (m, Ar-H, 5.97 (s, N-CH), 1.96 (s, CH3CN).

31P{1H} NMR (161 MHz, CDC13 ): 51.8 (s). Anal. Calcd for C56 H48 N4 B2 F8 P2 Fe : C, 62.95; H, 4.53; N, 5.24. Found: C, 62.69; H, 4.79; N, 5.81.

Preparation of catalyst (v): trans-[Fe(NCMe)(CO) {(R,R)-PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2} ] [BF4]2 Ph III
Phi (BF4)2 p~ lea'rN
p C:57 1 Ph Ph N Ph Ph C

(v) [0002501 A solution of trans-[Fe(NCMe)2 {(R,R)-PPh2C6H4CHNCHPhCHPhNCHC6H4PPh2}][BF4]2 (0.51 g, 0.5 mmol) in acetone was stirred under a 5 atm of CO at room temperature for 6 h. The solvents were evaporated, to obtain an orange powder. The powder was again dissolved in acetone and stirred under two atm of CO atmosphere for 12 h at room temperature.
The solvents were evaporated and the remaining orange residue was washed with toluene and ether. Crystallization from acetone/CH2C12/Et2O gave the analytical pure compound as an orange solid. Yield: 0.47 g (0.4 mmol, 80 %). 'H NMR (d3-MeCN, 300 MHz, 25 C): 6.05 (br s, 2 H, CH), 6.69-8.06 (several m, 30 H, Ph), 9.43 (br s, 2 H, CH=N). 31P NMR (CD2C12, 121 MHz): 49.9 (d, Jp,p = 39 Hz), 53.0 (d, Jp,p = 39 Hz). Anal. Calcd. for C55H45B2F8N3P2Fe1: C, 62.59; H, 4.30;
N, 3.98; Found: C, 61.93; H, 4.96; N, 3.67.

Preparation of catalyst(vi):
Fe(Ph2PCH2CH=NC2H4N=CHCH2PPh2)(CH3CN)2](BPh4h]

Me C
N
CP
I P BPh4]2 Ole Ph2 N Ph2 C
Me [0002511 Preparation of precursor solution (A): The reaction was performed in the glove-box under N2 atmosphere at room temperature. The diphenylphosphino-acetaldehyde hydrobromide dimer from Example 1 (200 mg, 0.324 mmol) was partially dissolved in CH3CN (6 mL). After 5 min of stirring [Fe(H20)6][BF4]2 (164 mg, 0.485 mmol) was added to the reaction mixture. t-BuOK (74.0 mg, 0.645 mmol) was added to the reaction mixture and the color of the solution changed from white to yellow. The mixture was stirred at room temperature for 30 min without any observable changes.

[0002521 A stock solution of the diamine was prepared by dissolving 85.5 mg of 1, 2-ethylenediamine in 1.1 mL of acetonitrile. A portion (0.250 mL) of stock solution was added to the precursor solution (A) over the course of 20 min at room temperature. The solution changed color to red-orange after the addition.
After 3 h the solution became deep orange. The solution was added to a solution of NaBPh4 (250 mg, 0.658 mmol) in 1.5 mL of MeOH to cause the formation of the precipitate. The orange-pink solid was filtered and washed with 0.35 mL of MeOH three times and dried under vacuum. Yield: 82% (0.33 mg); 1H NMR (400 MHz, CD3CN) J: 1.36 (s, 6H, CH3CN ), 4.10-4.25 (m, 4H, HCP), 4.10-4.25 (m, 4H, HC-N), 6.80-7.55 (m, 60H, ArH), 8.65-8.80 (m, 2H, HC=N). 31P {H} NMR
(121 MHz; CD3CN): 74.01 ppm (s). Anal. Calcd for C82H76N4P2FeB2: C, 78.38;
H, 6.08; N, 4.46. Found: C, 77.58; H, 6.03; N, 4.26. MS (ESI+) Calcd. for [C34H36N4P2Fe-2(CH3CN)]2+: 268.2 m/z. Found: 268.1 m/z. MS (ESI-) Calcd for [B(Ph)4]-: 319.2 m/z. Found: 319.2 m/z. The crystals were obtained by diffusion of Et2O (1.0 mL) into the deep orange solution (1 mL) obtained as above but before the addition of NaBPh4.

Preparation of catalyst (vii):
[Fe(Ph2PCH2CH=NC2H4N=CHCH2PPh2)(CH3CN)(CO)](BPh4)2 Co r-I -\
PiFeP I BPh41 2 C
Ph2 N Ph2 C
Me [0002531 The complex [Fe(Ph2PCH2CH=NC2H4N=CH-CH2PPh2)(CH3CN)2](BPh4)2 (vi) (200 mg, 0.159 mmol) was dissolved in (10 mL) of degassed acetone under inert atmosphere. Resulting solution was placed in the CO high pressure reactor and was stirred under 5 atmosphere of CO for 12 hours at room temperature. Solvent was evaporated under reduced pressure and resulting solid was washed with diethyl ether (5 mL) three times. Yellow solid was dried under vacuum. Yield of (vii): 80 % (158 mg); 1H NMR (400 MHz, acetone-d6) 3: 1.72 (s, 3H, CH3CN), 3.95-4.50 (m, 4H, HC-N), 3.95-4.50 (m, 4H, HCP), 6.55-7.89 (m, 60H, ArH), 8.18-8.46 (m, 2H, HC=N); 31P {H} NMR (121 MHz; acetone-d6): 69.1 ppm (s).

Preparation of trans-[Fe(MeCN)2(6)](BF4)2, wherein 6 is `N CnN~ k4l \/ PPh2 Ph2P \ /
where n = 2 [0002541 This ligand 6 was prepared as described in Jeffery, J. C.;
Rauchfuss, T. B.; Tucker, P. A. Inorg. Chem. 1980, 19, 3306-3316. The complex trans- [Fe(MeCN)2(6)](BF4)2 was prepared as follows. A suspension of 6 (149 mg, 0.25 mmol) in 5 mL of MeCN was added to a solution of [Fe(H20)6][BF4]2 (84 mg, 0.25 mmol) in MeCN (10 mL). After stirring for 1 h, the red solution was concentrated to 1 mL and 10 mL of Et2O was added. A purple powder precipitated. The powder was isolated and washed with hexane. (200 mg, 87%).
Crystals suitable for X-ray diffraction studies were obtained from a McCN/Et20 solution. 'H NMR (400 MHz, CDC13): 9.46 (s, CH=N), 8.07-6.71 (m, ArH), 4.35 (s, CH2), 2.00 (s, CH3CN); 31P{1H} NMR (161 MHz, CDC13) 54.4 (s). Anal.
Calcd for C44H40N4B2F8P2Fe: C, 57.68; H, 4.40; N, 6.12%. Found: C, 57.16; H, 4.40; N, 5.86%.

Preparation of catalyst (viii): trans-[Fe(MeCN)(CO) (6)](BF4)2 ~9 -7 (BF4)2 ~N `N

Ph P N Ph Ph C
(viii) [0002551 Complex trans-[Fe(MeCN)2(6)](BF4)2 was reacted with CO (2 atm) in acetone at room temperature to produce complex (viii). Yield: 1.14 g (1.3 mmol, 87 %.). 1H NMR (d3-MeCN, 300 MHz): 1H NMR 4.01 (br s, 4 H, CH2), 7.20-7.98 (several m, 20 H, Ph), 9.21 (br s, 2 H, CH=N). 31P NMR (CD2C12, 121 MHz): 50.8 (s). Anal. Calcd. for C43H37B2F8N3P2Fe1: C, 57.18; H, 4.13; N, 4.65; Found: C, 56.12; H, 4.15; N, 4.83.

Preparation of complex: trans-(R,R)-[Fe(MeCN)2(PPh2CH2 CHNC6H 10NCHCH2PPh2)] (BF4)2 ,N,,, .N
C
P~Fe~P_ [BPh4]2 Ph2 I Ph2 [0002561 The diphenylphosphino-acetaldehyde hydrobromide dimer from Example 1 (200 mg, 0.324 mmol) was completely dissolved in MeOH (6 mL).
[Fe(H2O)6][BF4]2 (164 mg, 0.485 mmol) was added to the reaction mixture.

NaOMe (34.9 mg, 0.647 mmol) was added as a MeOH (1 mL) solution and the color of the solution changed from colorless to clear yellow. After 10 min of stirring, 1 mL of acetonitrile was added to give precursor solution B.

[000257] (1R,2R)-(-)-1,2-diaminocyclohexane (37 mg, 0.32 mmol) was dissolved in 0.5 mL of acetonitrile and was added to the precursor solution over the course of 20 min. The solution changed color to purple after addition. The resulting solution was heated at 40 C for 20 h to give a deep orange solution. The solvent volume was reduced by one half and the resulting solution was added to a solution of NaBPh4 (250 mg, 0.658 mmol) in 1.5 mL of MeOH to cause the formation of a precipitate. An orange-red solid was recovered by filtration and washed with 0.15 mL of MeOH three times and dried with vacuum. Yield: 54%
(0.23 mg); 1H NMR (400 MHz, CD3CN) 6: 1.33 (s, 6H, CH3CN), 1.29-1.39 (m, 2H, H of C6H1o), 1.68-1.76 (m, 2H, H of C6H10), 1.98-2.28 (m, 2H, H of C6Hlo), 2.70-2.78 (m, 2H, H of C6H10), 3.54-3.58 (m, 2H, HC-N), 3.88-4.01 (m, 2H, HCP), 4.34-4.49 (m, 2H, HCP), 6.8-7.5 (m, 60H, ArH), 8.60-8.74 (m, 2H, HC=N). 31P {H} NMR (121 MHz; CD3CN): 73.96 ppm (s). Anal. Calcd for C86H82N4P2FeB2: C, 78.78; H, 6.31; N, 4.27. Found: C, 77.00; H, 5.99; N, 4.34.
MS (EST) Calcd for [C38H42N4P2Fe-2(CH3CN)]2+: 268.1 m/z. Found: 268.1 m/z.
MS (ESt) Calcd for [B(Ph)4]-: 319.2 m/z. Found: 319.2 m/z.

Preparation of trans-(R,R)-[Fe(CO)(NCMe)(PPh2CH2CHNC6H10NCHCH2PPh2)](BF4)2 C P P 1 11* 1 [BPh412 Ph2 Ph2 C
III

[0002581 The complex was prepared according to the method of example 9.
31P NMR(H) d (66.78, 67.05) and d(70.52, 70. 79) J=81 Hz.

Preparation of complex: trans-[Fe(MeCN)2(PPh2CH2CHNC6H4NCHCH2PPh2)](BF4)2 N/ ~N
PF6`P [BPh4]2 Ph2 Ph2 [0002591 Ortho-phenylenediamine (35 mg, 0.32 mmol) was dissolved in 0.5 mL of acetonitrile and was added to the precursor solution (A) of Example 8 over the course of 20 minutes at 22 C. The solution changed color to orange after the addition. The resulting residue was added to the solution of NaBPh4 (250 mg, 0.658 mmol) in 1 mL of MeOH to cause the formation of the precipitate. The red-orange solid was isolated by filtration and washed with 0.15 mL of MeOH three times and dried under vacuum. Yield: 86% (0.36 mg); 'H NMR (400 MHz, CD3CN) 6: 2.10 (s, 6H, CH3CN), 4.52-4.60 (m, 4H, HCP), 6.80-8.20 (m, 64H, HAr), 9.32-9.44 (m, 2H, HC=N). 31P {H} NMR (121 MHz; CD3CN): 68.33 ppm (s). Anal. Calcd for C38H36N4P2FeB2: C, 79.19; H, 5.87; N, 4.29. Found: C, 76.83;
H, 5.80; N, 4.15. MS (ESI) Calcd for [C86H76N4P2Fe-2(CH3CN)]2+: 292.2 m/z.
Found: 292.1 m/z. MS (ESIF) Calcd for [B(Ph)4]": 319.2 m/z. Found: 319.2 m/z.

Example 15 [0002601 Preparation of the dicyclohexylphosphino-acetaldehyde hydrobromide dimer Cy2P OH (Br)2 ~
HO PCy2 meso- and rac-[ 0 0 0 2 611 A Schlenk flask was charged with dicyclohexylphosphine (2.53 g, 0.013 mol) and dry THE (10 mL). Bromoacetaldehyde diethyl acetal (2.50 g, 0.013 mol) was added over the course of 15 min. The mixture was stirred for 1 hour, at which time a white precipitate was evident. An excess amount of degassed water (1 mL) was added and the mixture was allowed to reflux overnight to yield a pristine white sludge. The solid was collected by filtration under air and washed with water (2 x 3 mL) and diethyl ether (2 x 3 mL).
Drying in vacuo yielded the phosphonium dimer as an air-stable white powder. Yield:
3.25 g (80%); 1H NMR (400 MHz, CD3CN) 6: 1.42 - 2.19 (m, HCy), 2.80 (q), 3.08 (m), 5.39 (dd, JHP = 26 Hz, JHH = 4 Hz), 5.23 (dd, JHP = 22 Hz, JHH= 4 Hz).
31p {1H} NMR (121 MHz; CD3CN) 3: 27.2 (s), 28.1 (s). Anal. Calcd for C28H52O2P2Br2: C, 52.35; H, 8.16. Found: C, 51.93; H, 8.46. MS (ESI, methanol/water; m/z+): 241.2 [C28H52O2P2]2+.
Example 16 Preparation of complex:
[Fe(Cy2P CH2CH=NC2H4N=CHCH2P Cy2)(CH3 CN)2] (BPh4)2]

/--\
CNP N
~F6" Pj [BPh4]2 [0002621 A vial was charged with the dicyclohexylphosphino-acetaldehyde hydrobromide dimer (200 mg, 0.311 mmol), KOtBu (70 mg, 0.623 mmol) and CH3CN (4 mL). After stirring for 5 minutes, [Fe(H20)6][BF4]2 (158 mg, 0.467 mmol) in CH3CN (2 mL) was added to the white slurry. The solution turned grey-yellow after 5 minutes; ethylenediamine (0.34 mL from a stock solution of 200 mg in 4 mL CH3CN) was added. The mixture turned pink immediately.
After the reaction has gone to completion overnight, the mixture was filtered through a pad of Celite to remove a grey-white precipitate. Solvent was removed under reduced pressure to give a red-pink residue. The solid was dissolved in MeOH (2 mL) and added to a solution of NaBPh4 (234 mg, 0.685 mmol) in MeOH (1 mL) to cause precipitation of a pale pink solid. The solid was filtered and washed with MeOH (2 x 1 mL) and dried under vacuum. Yield: 80% (319 mg). Single crystals suitable for an X-ray diffaction study were obtained by slow diffusion of pentane into CH3CN/CH2C12 (1:1 by volume) at -40 C. 'H NMR
(400 MHz, CD3CN) 6: 1.11 - 1.95 (m, HCy, CH3), 3.31 (d, 4H, H2CP), 3.95 (s, 4H, H2C-N), 6.8-7.3 (m, HAr), 8.41 (m, 2H, HC=N). 13C {1H} NMR (100 MHz, CD3CN) 6: 26.58 (Ccy), 27.63 (t, Jcp = 5.1 Hz, Ccy), 27.82 (t, JcP = 5.1 Hz, Ccy), 29.87 (Ccy), 30.04 (Ccy), 35.72 (t, Jcp = 6.9 Hz, CcyP), 36.92 (dd, Jcp = 15, 10 Hz, CH2P), 61.10 (CH2N), 122.61 (CphB), 126.43 (q, JcB = 2.7 Hz, CPhB), 136.58 (q, JcB = 1.4 Hz, CPhB), 164.62 (m, JcB = 49 Hz, CphB), 177.86 (HC=N). 31P {1H}
NMR (161 MHz, CD3CN) 8: 68.5 (s). Anal. Calcd for C82H100N4P2FeB2: C, 76.88; H, 7.87; N, 4.37. Found: C, 71.23; H, 7.51; N, 4.47. MS (ESI, methanol/water; m/z+): 505.4 [C3oH5sN2P2-(Fe(NCCH3)2)]+

Example 17 Preparation of catalyst precursor:
[Fe(Cy2PCH2CH=NC2H4N=CHCH2PCy2)(Br)(CO)] [BPh4]
CO

PV' 6" P Nw'~) [BPh4]
CY2I Cy2 Br [0002631 A vial was charged with the dicyclohexylphosphino-acetaldehyde hydrobromide dimer (200 mg, 0.311 mmol), KOtBu (70 mg, 0.623 mmol) and CH3CN (4 mL). After stirring for 5 minutes, [Fe(H20)6][BF4]2 (158 mg, 0.467 mmol) in CH3CN (2 mL) was added to the white slurry. The solution turned grey-yellow after 5 minutes; ethylenediamine (0.34 mL from a stock solution of 200 mg in 4 mL CH3CN) was added. The mixture turned pink immediately.
After the reaction has gone to completion overnight, the mixture was filtered through a pad of Celite to remove a grey-white precipitate and then transferred to a Shlenk flask. Solvent was removed under reduced pressure to give a red-pink residue. Acetone (15 mL) was added and the solution was stirred under constant flow of CO overnight. The resulting yellow-brown solution was evaporated to dryness, dissolved in MeOH (2 mL) and added to a solution of NaBPh4 (94 mg, 0.274 mmol) in 1 mL of MeOH to cause formation of a yellow precipitate. Yield:
63% (150 mg). Single crystals suitable for an X-ray diffaction study were obtained by slow diffusion of hexanes into THF. 1H NMR (400 MHz, CD2C12) 6:
1.20-1.39 (m, HCy), 2.50 (br. m, 2H, HCyP) 2.86 (dd, JHP = 19.0 Hz, 2H, HCP), 3.27 (dd, JHP = 20.0 Hz, 2H, HCP), 3.44 (m, JHH = 6.2 Hz, 2H, HCN), 3.81 (m, JHH = 5.6 Hz, 2H, HCN), 6.88-7.39 (m, HAr), 7.49 (m, 2H, HC=N). 13C {1H}
NMR (100 MHz, CD2CI2) S: 26.34 (d), 27.80 (m), 29.47 (t), 30.24, 30.75 (d), 38.29 (q), 39.73 (dd), 60.93, 105.35, 122.65, 126.52, 136.71, 164.01-165.68 (m, Jc_B 49 Hz), 174.42. 31P {1H} NMR (161 MHz, CD2C12) S: 69.78 ppm. IR (KBr) 1948 cm-1 (vc ao). Anal. Calcd for C55H74BBrFeN2OP2: C, 66.88; H, 7.55; N, 2.84; Found: C, 65.30; H, 7.89; N, 3.15.
Example 18 Preparation of the di(p-tolyl)phosphino-acetaldehyde hydrobromide dimer.
N~Q' XC~ - 18rI2 P
HO OH
P
meso- and rac-[0002641 A Schlenk flask was charged with KH (0.524 g, 13.1 mmol), and dry THE (13 mL). Di(p-tolyl)phosphine (2.331 g, 10.9 mmol) was added, and the solution turned red in colour. The solution was stirred for 30 min, and then cooled to -78 C. Bromoacetadehyde diethyl acetate (1.68 mL, 10.9 mmol) was added over 20 min, and the solution turned yellow. The solution was warmed to room temperature and 48% HBr (2.5 g, 14.8 mmol) was added. A white precipitate formed, and the solution turned colourless. The mixture was heated at 45 C for 2 hours, and then left in the freezer overnight. The precipitate was filtered off and washed with 15 mL cold H2O, as well as 15 mL of a 1:1 mixture of cyclohexanol:ethyl acetate. The precipitate was then recrystallized in MeOH
and ether, and dried under high vacuum. Yield: 2.698 g, 87.8%. Diastereomer 1 :
1H NMR (CD3OD, 400 MHz, S): 8.06 (dd, J= 8.2, 12.3, aromatic CH, 4H), 7.63-7.58 (m, aromatic CH, 8H), 7.48 (dd, J= 2.5, 8.2, aromatic CH, 4H), 6.19 (dd, J=
6.8, 21.5, PCH(OH), 2H), 4.37-4.15 (m, H1 of PCH(OH)CH2, 2H), 3.99-3.81 (m, H2 of PCH(OH)CH2, 2H), 2.53 (s, CH3, 6H), 2.44 (s, CH3, 6H). 31P NMR
(CD3OD, 400 MHz, S): 11.12. 13C NMR (CD3OD, 400 MHz, S): 146.8 (aromatic C-P), 146.7 (aromatic C-P), 133.7 (aromatic CH), 133.1 (aromatic CH), 130.6 (aromatic CH), 130.4 (aromatic CH), 113.9 (CH3C), 113.0 (CH3C), 61.1 (PCHOH), 22.1 (PCH2), 20.5 (CH3), 20.3 (CH3). Diastereomer 2: 1H NMR
(CD3OD, 400 MHz, S): 7.96 (dd, J= 8.3, 12.5, aromatic CH, 4H) , 7.86 (dd, J=

8.3, 12.0, aromatic CH, 4H), 7.63-7.58 (m, aromatic CH, 4H), 7.56 (dd, J= 3.2, 8.3, aromatic CH, 4H), 5.80 (ddd, J= 2.5, 9.4, 16.3, PCH(OH), 2H), 4.37-4.15 (m, Hl of PCH(OH)CH2, 2H), 3.99-3.81 (m, H2 of PCH(OH)CH2, 2H), 2.50 (s, CH3, 6H), 2.49 (s, CH3, 6H). 31P NMR (CD3OD, 400 MHz, S): 16.06. 13C NMR
(CD3OD, 400 MHz, 5): 147.5 (aromatic C-P), 146.9 (aromatic C-P), 133.3 (aromatic CH), 132.9 (aromatic CH), 131.3 (aromatic CH), 130.5 (aromatic CH), 112.5 (CH3C), 111.7 (CH3C), 62.2 (PCHOH), 23.6 (PCH2), 20.4 (CH3). Anal.
Calcd for [C32H36P2O2][Br]2[CH3OH][H2O]: C, 54.71; H, 5.84. Found: C, 54.65;
H, 6.04. MS (ESI, methanol/water; m/z+): 257.1 [C32H36O2P2]2+. The diastereomeric excess was found to be 13%, as determined by 1H NMR, and 31P
NMR.

Example 19 Preparation of catalyst precursor:
[Fe((C7H7)2PCH2CH=NCHPhCHPhN=CHCH2P(C7H7)(CH3CN)2] (BPh4)2]

NCCH3 I BPh412 Ph, -e Ph cf P Fe:P~
tol p I tol tol tol [0002651 A vial was charged with the di(p-tolyl)phosphino-acetaldehyde hydrobromide dimer (235 mg, 0.324 mmol), and CH3CN (4 mL). A yellow solution of [Fe(H2O)6][BF4]2 (164 mg, 0.485 mmol) in CH3CN (2mL) was added to the white slurry, followed by NaOMe (34.9 mg, 0.647 mmol) in MeOH (1 mL).
The color of the solution changed from yellow to colourless. After 20 min of stirring (1R,2R)-(+)-1,2-diphenylethylenediamine (69 mg, 0.323 mmol) in 0.5 mL
of acetonitrile was added over 5 min, and [0002661 the solution turned deep purple. After 48 h the mixture was filtered to remove a white precipitate. The solvent was removed under reduced pressure to give a red-pink residue. The residue was dissolved in MeOH (2 mL) and added to a solution of NaBPh4 (250 mg, 0.658 mmol) in MeOH (1 mL) to cause precipitation of a pale pink solid. The product was filtered and washed with MeOH (2 x 5 mL) and dried under vacuum. Yield: 26.3% (120 mg). Crystals suitable for X-ray diffraction studies were obtained by slow diffusion of Et20 into CH3CN/MeOH (1:5 by volume). 1H NMR (400 MHz, CD3CN) 6: 2.20 (s, 6H, CH3CN), 3.90-4.03 (m, 2H, HCP), 4.15-4.30 (m, 2H, HCP), 5.42 (m, 2H, HC-N), 6.80-7.75 (m, 74H, aromatic H), 8. 90-8.20 (m, 2H, HC=N). 31P {1H} NMR (121 MHz; CD3CN) S: 70.52 ppm (s). Anal. Calcd for [C98H92N4P2FeB2: C, 80.33; H, 6.33; N, 3.82, Found: C, 76.31; H, 6.71; N, 3.77. MS (ESI, methanol/water;
m/z+):
372.1 [C5oH52N4P2Fe]2+.

Example 20 CO I BPh4]
Ph, I-ePh cP,F.P
tol I tol tol tol Br [0002671 Following the same steps as in the synthesis of Example 19, the reaction mixture that was stirred for 48 h was filtered and transferred to a Schlenk flask. The solvent was removed under pressure, and acetone (9 mL) was added.
The solution was stirred under a constant flow of CO overnight. The resulting yellow-brown solution was evaporated to dryness, dissolved in MeOH (4 mL) and added to a solution of NaBPh4 (125 mg, 0.329 mmol) in MeOH (1 mL) to cause formation of a yellow precipitate. Yield: 22.2% (108 mg). 31P {1H} NMR (121 MHz; C6D6 insert) 6: 65.96 (d, J = 39.5 Hz), 67.93 ppm (d, J = 39.5 Hz).

General procedure for Examples 21 and 22 [0002681 In an Ar-filled glovebox diisopropylphosphine (for Example 21) or diethylphosphine (for Example 22) (15 mmol) was dissolved in 20 mL of dry THF. Bromoacetadehyde diethyl acetal (15 mmol) was added to the resulting mixture on Ar line and resulting solution was stirred for 4 h. The reaction was quenched with degassed H2O (8 mL) and heated for over night at 45 C. The solvent was partially removed under vacuum and to give colorless solution with white precipitate. The solution was stored for 3 h at 5 C. The precipitate then was filtered and washed with pre-cooled water (15 mL) and diethyl ether (10 mL) to give an analytically pure sample. Crystals suitable for X-ray diffraction experiments were obtained by slow diffusion of diethyl ether into a saturated solution of Example 22 in methanol.

Example 21 OH (Br)2 Prig JP
HO"" PiPr2 meso- and rac-Properties of the di(i-propyl)phosphino-acetaldehyde hydrobromide dimer [0002691 Yield: 2.93 g, 81 %. The diastereomeric ratio was found to be 1:2, as determined by 1H NMR. 'H NMR (400 MHz, CD3OD, resonances of two diastereomers overlap in region 6 3.50-1.40; see below): 6 5.60 (pseudo ddd, = 6.4 Hz, 2JHP= 22.3Hz, 2H, CH(OH), major diastereomer; 31P{'H}, 5.60 (pseudo d, 3JHH = 6.5Hz)), 5.44 (ddd, 1H, 3JHH = 3.0Hz, 3JHH = 9.3 Hz, 2JHP = 12.0 Hz, 2H, CH(OH), minor diastereomer; 1H{31P}55.44 (dd, 3JHH= 3.0 Hz, 3JHH = 9.3 Hz)), 3.50-2.85 (m, overlap of 4H, CH(OH)CH2P and 4H, (CH3)2CHP (both diastereomers); 'H{31P}, same), 1.60-1.40 (m, 12H, (CH3)2CHP, (both diastereomers); IH{31P}, same). 31P{1H} NMR (161 MHz, CD3OD): 6 36.81 (s, minor diastereomer), 34.54 (s, major diastereomer). 13C{1H} NMR (100 MHz, CD3OD, signals of carbon atoms appear as a multiplets with complex splitting patterns that arise from coupling to two magnetically inequivalent phosphorus atoms in the structure ): 6 58.61 (m, CH(OH), minor diastereomer), 57.69 (m, CH(OH), major diastereomer), 22.93 (m, CH2P, major diastereomer), 22.93 (m, CH2P, minor diastereomer), 21.23 (m, CH2P, major diastereomer), 21.62 (d, 2Jcp = 21.8 Hz, C(CH3)2P, minor diastereomer) 19.71 (d, 2Jcp = 40.5 Hz, C(CH3)2P, major diastereomer), 16.45-15.35 (m, overlapping peaks of isopropyl methyl groups, both diastereomers). Anal. Calcd for C16H36P2O2Br2: C, 39.85; H, 7.52.
Found: C, 39.35; H, 7.32.

Example 22 Et2POH (Br)2 HO PEt2 meso- and rac-Properties of the di(ethyl)phosphino-acetaldehyde hydrobromide dimer [0002701 Yield: 1.28 g, 40%. The diastereomeric ratio was found to be 1:2, as determined by 'H NMR. 'H NMR (400 MHz, CD3OD, resonances of two diastereomers overlap; see below): S 5.45-510 (m, 2H, CH(OH), diastereomers overlap; 'H{31P}, 5.36 (pseudo d, 2H, CH(OH), 2JH_P = 5.8 Hz, major diastereomer), 5.29 (pseudo dd, 2H, CH(OH), 3JH_H = 3.4Hz, 2JH_P = 9.2 Hz, minor diastereomer)), 3.31-2.87 (m, 4H, CH(OH)CH2P, overlap of diastereomers;
'H{31P}, same), 2.58-2.08 (m, 8H, (CH3CH2P, overlap of diastereomers; 'H{31P};
same), 1.32-0.90 (m, 12H, CH3CH2P, overlap of diastereomers; 'H{31P}, same).
31P{1H} NMR (161 MHz, CD3OD): S 35.59 (s, minor diastereomer), 32.72 (s, major diastereomer). 13C{'H} NMR (100 MHz, CD3OD, complex coupling of several carbon atoms results from coupling to two magnetically unequivalent phosphorus atoms in the structure ): S 58.10 (m, CH(OH), minor diastereomer), 57.85 (m, CH(OH), major diastereomer), 19.54 (m, CH2P, minor diastereomer), 18.35 (m, CH2P, major diastereomer), 12.50-9.12 (m, CH3CH2P, overlap of diastereomer), 5.42-3.72 (m, CH3CH2P, overlap of diastereomer). Anal. Calcd for C12H28P2O2Br2: C, 33.82; H, 6.62. Found: C, 33.92; H, 6.38.

[00027 1] While the present invention has been described with reference to examples, it is to be understood that the invention is not limited to the disclosed examples. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0002721 All publications, patents and patent applications are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

What is claimed is:
A hexa-coordinate iron (II) complex comprising a compound of formula (I):
R6 R7 171+

a Ra N L `N~ R
Fe A
P L2 P\

(I) wherein each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;
A is selected from:
'''s; and \ R3 /ny wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;
each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;

each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from and each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
L' and L2 are independently selected from the group consisting of CO; hydride;
pyridine and derivatives thereof; imidazole and derivatives thereof; halide ion;
NCR, CNR and "OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR`N wherein Ra, Rb, and Rc are independently selected from the group consisting of H and C1-C2 alkyl; and R (CO)Rd wherein Rc and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl;
m represents the charge of the compound of formula (I) and is 0, +1, or +2;
and when m is +1 or +2, the iron (II) complex comprises at least one counter ion to counterbalance the charge of the compound of formula (I);

with the proviso that when A is / , then at least one of L' and L2 must be selected from the group consisting of CO and CNR, wherein R is as defined above.

The hexa-coordinate iron (I1) complex of claim 1, wherein a trans coordination geometry is achieved at iron through nitrogen and phosphorus donor bonds of a tetradentate diimino-diphosphine templated ligand of the formula (II):
R'2P-A-C(R4)=N-C*(RR)-C*(RR8)-N=C(R4)-A-PR12 (II) and Ll and L2 are in an axial coordination above and below the templated ligand, respectively.
The hexa-coordinate iron (II) complex of claim 1, wherein the at least one counter ion is selected from the group consisting of BF4 ; PF6 SbF6 ; C1O4-; CH3SO3-;
CF3SO3-; C6H5SO3 ; p-CH3C6H4SO3-; FeC142 FeBr42-; B(R*)4 , wherein R* is selected from the group consisting of phenyl, C6H3(CF3)2 and C6F5; halides;
pseudohalides; CI-C8 alkoxides; and aryloxides.
The hexa-coordinate iron (II) complex of claim 3, wherein Rl is phenyl.

The hexa-coordinate iron (II) complex of claim 4, wherein A is / ; R4 is H;
R5, R6, R7 and R8, together with the carbon atoms to which they are attached, combine to form L' is CH3CN; L2 is selected from the group consisting of CH3CN, CO and CNtBu; and m is +2.
The hexa-coordinate iron (II) complex of claim 5, wherein the chiral carbon atoms denoted by asterisks:
both have an R configuration, or both have an S configuration.

The hexa-coordinate iron (II) complex of claim 4, wherein A is / ; R4 is H; R5=R6=R7=R8=H; L' is CH3CN; L2 is selected from the group consisting of CH3CN, CO and CNtBu; and m is +2.

The hexa-coordinate iron (II) complex of claim 4, wherein A is / ; R4 is H;
R5= R8=phenyl; R6 = R7 = H; L' is CH3CN; L2 is selected from the group consisting of CH3CN, CO, and CNtBu; and m is +2.
The hexa-coordinate iron (II) complex of claim 8, wherein the chiral carbon atoms denoted by asterisks:
both have an R configuration, or both have an S configuration.

The hexa-coordinate iron (II) complex of claim 4, wherein A is R3 n wherein R2=R3=H, and n=1; R4 is H; R5=R8= phenyl; R6=R7=H; L' is CH3CN; L2 is selected from the group consisting of CH3CN, CO, and CNtBu; and m is +2.
The hexa-coordinate iron (II) complex of claim 10, wherein the chiral carbon atoms denoted by asterisks:
both have an R configuration, or both have an S configuration.

The hexa-coordinate iron (II) complex of claim 4, wherein A is R An-~ , wherein R2=R3=H, and n=1; R4 is H; R5=R6=R7=R8=H; Ll is CH3CN; L2 is selected from the group consisting of CO and CNtBu; and m is +2.
The hexa-coordinate iron (II) complex of claim 1 wherein the compound of formula (I) has the structure:
Ph NCCH3 7 2+
N, Fe""" Poe P

Ph2 Ph2 (III).
The hexa-coordinate iron (II) complex of claim 13, wherein the chiral carbon atoms denoted by asterisks:

both have an R configuration, or both have an S configuration.
A process for the preparation of a hexa-coordinate iron (II) complex of claim 1, the process comprising reacting a phosphinaldehyde precursor of formula (V):

OH 2+
R12P' -fLR4 R4LA,PR12 HO
M
wherein each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal RI groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

R3 ~ny A is , wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;
each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;
with a diamine of formula (VI):

R61~~Ra (VI) wherein each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from and each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
in the presence of:
an iron (II) salt;
a ligand selected from the group consisting of CH3CN; pyridine and derivatives thereof; and imidazole and derivatives thereof; and a strong base;
to form the compound of formula (I) 7 m+

* * 4 (I) wherein A, R1-R8, and n are as defined above, in is +2, L' and L2 are both CH3CN; pyridine or a derivative thereof; or imidazole or a derivative thereof;
and adding at least one counter ion to counterbalance the charge of the compound of formula (I).
The process of claim 15 wherein the compound of formula (1) is further reacted with CO; hydride; halide ion; NCR, CNR or OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbRCN wherein Ra, Rb, and Re are independently selected from the group consisting of H and C1-C2 alkyl; or Rc(CO)RR wherein R and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl, to produce a compound of formula (VIIIa):

R6 R7 R8 M+
RS
* * 4 RYA L ' A- P..,-. L' p A
R I R 1 Rl RI
(VIIIa) wherein A, R1-R8, and n are as defined for formula (I), L1 is CH3CN; pyridine or a derivative thereof; or imidazole or a derivative thereof;
and L2' is selected from the group consisting of CO; hydride; halide ion; NCR, CNR
or OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR`N wherein Ra, Rb, and R are independently selected from the group consisting of H and C1-C2 alkyl; or R (CO)Rd wherein R and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl, and m is +1 or +2.
The process of claim 16 wherein the phosphinaldehyde precursor is:

Ph2POH
HO PPh2 the diamine is:
Ph Ph and the product is a compound of formula (I) having the structure:
Ph NCPhH3 2+

c7p~ F eP
Ph2l Ph2 (III).
The process of claim 17, wherein the chiral carbon atoms denoted by asterisks:
both have an R configuration, or both have an S configuration.
A process for preparing an alcoholic compound wherein said process comprises a step of preparing the alcoholic compound by reducing a ketone or aldehyde with the reaction of hydrogen or a compound donating hydrogen in the presence of a hexa-coordinate iron (II) complex of claim 1, with the proviso that the ketone is not an unsubstituted cycloalkanone.
The process of claim 19, wherein the hexa-coordinate iron (II) complex comprises a compound of formula (I) having the structure:

Ph\\ N ph 3 2+
CPIFe~P~
Ph2 Ph2 (III) and the chiral carbons atoms denoted by asterisks:
both have an R configuration; or both have an S configuration, and the reaction uses hydrogen.

A process for preparing an amine compound wherein said process comprises a step of preparing the amine compound by reducing an imine with the reaction of hydrogen or a compound donating hydrogen in the presence of a hexa-coordinate iron (II) complex of claim 1.
The process of claim 21, wherein the hexa-coordinate iron (II) complex comprises a compound of formula (I) having the structure:
Me IICI
N77 (BF4)2 _N
Fe \ / Ph.11, 1 11 P
2 co Ph2 and the chiral carbons atoms denoted by asterisks:
both have an R configuration; or both have an S configuration, and the reaction uses a compound donating hydrogen.

A hydrogenation catalyst comprising a hexa-coordinate iron(II) complex of formula (1) R6 R7 M+

' 4 a R
RAN, 1 %N=r Fe" ' . A
A-. 1 2 (I) wherein a trans coordination geometry is achieved at iron through nitrogen and phosphorus donor bonds of a tetradentate diimino-diphosphine templated ligand of the formula (II):
R12P-A-C(R4)=N-C*(RR6)-C*(R7R)-N=C(R4)-A-PR12 (II) and L' and L2 are in an axial coordination above and below the templated ligand, respectively, wherein the tetradentate diimino-diphosphine templated ligand is the reaction product of a phosphinaldehyde precursor of formula (V) OH 2+

R4.~PR12 HO A
M
and a diamine precursor of formula (VI) (VI) wherein each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-Cg alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R' groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R1 groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

A is R3 n wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;
each R5, R6, R' and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from Z and / \

each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
Ll and L2 are independently selected from the group consisting of CO; hydride;
pyridine and derivatives thereof; imidazole and derivatives thereof; halide ion;
NCR, CNR and "OR, wherein R is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl and cycloalkyl, all of which may be optionally substituted; RaRbR`N wherein Ra, Rb, and R are independently selected from the group consisting of H and C1-C2 alkyl; and R (CO)Rd wherein R and Rd are independently selected from the group consisting of C1-C8 alkyl, aryl, and heteroaryl;
m represents the charge of the compound of formula (I) and is 0, +1, or +2;
and when m is +1 or +2, the iron (II) complex comprises at least one counter ion to counterbalance the charge of the compound of formula (I);

with the proviso that when A is then at least one of L1 and L2 must be selected from the group consisting of CO and CNR, wherein R is as defined above.

A process for the preparation of a hexa-coordinate iron (II) complex of claim 1, the process comprising reacting a phosphinaldehyde precursor of formula (V):

OH 2+
R12P'A R4 HO
(V) wherein each R1 is independently selected from the group consisting of aryl, heteroaryl, C1-C8 alkyl, C2-C8 alkenyl, C1-C8 alkoxy, aryloxy, and cycloalkyl, all of which may be optionally substituted; two geminal R1 groups may combine to form a C2-C4 linear alkyl diradical or C3-C8 branched alkyl diradical, each of which may be optionally substituted, to form a ring together with the phosphorus atom to which they are attached; or two R' groups, each of which is located on a different phosphorus atom, may combine to form a linker M, wherein M is selected from the group consisting of C2-C4 linear alkyl diradical and C3-C8 branched alkyl diradical, each of which may be optionally substituted, or M may be a diradical ligand with a wide bite angle;

A is R3 ~ny;

wherein each R2 and R3 are independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl, and each n is an integer independently selected from 1, 2, and 3;

each R4 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-Cg alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl;
with a diamine of formula (VI):

R61~ R8 (VI) wherein each R5, R6, R7 and R8 is independently selected from the group consisting of H, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted aryl, and substituted or unsubstituted cycloalkyl; R5 and R6, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; R7 and R8, together with the carbon atom to which they are attached, may combine to form a substituted or unsubstituted cycloalkyl ring of size from 5-8 carbons; or R5, R6, R7 and R8, together with the carbon atoms to which they are attached, may combine to form a group selected from * ,and each of which may be optionally substituted with one or more substituents selected from the group consisting of C1-C8 alkyl, C1-C8 alkoxy, and halogen atoms;
in the presence of:
an iron (II) salt;
a ligand selected from the group consisting of CH3CN; pyridine and derivatives thereof; and imidazole and derivatives thereof; and a strong base;
and further reacting the reaction product of the foregoing steps with CO to produce a compound of formula (VIIIa):

R6 R7 M+

RY,, L1 R
A. / i 2 `P,A
L
R1 R1 R Rl (VIIIa) wherein A, R'-R8, and n are as defined above, L1 is CO, L2' is Br, and m is +1;
and adding a counter ion to counterbalance the charge of the compound of formula (VIIIa).
A process for preparing a phosphonium dimer of formula (XIII) is provided:

P

HO
RI/ P\ RI
(XIII) wherein R1 is selected from the group consisting of C1-C8 alkyl, C1-C8 substituted alkyl, cycloalkyl, and substituted cycloalkyl, and X is selected from the group consisting of Br and I, the process comprising:
reacting a compound of formula (XI):
HPR12 (XI) wherein R1 is as defined above;
with a compound of formula (XII):
O.ARe X O_Re (XII) wherein X is as defined above, and Re is C1-C8 alkyl, or the two Re can combine to form a C2-C3 linear alkyl diradical;
and heating the reaction product in the presence of water to form the phosphonium dimer of formula (XIII).