Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
  • B01J31/18—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes containing nitrogen, phosphorus, arsenic or antimony as complexing atoms, e.g. in pyridine ligands, or in resonance therewith, e.g. in isocyanide ligands C=N-R or as complexed central atoms
  • B01J31/1805—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes containing nitrogen, phosphorus, arsenic or antimony as complexing atoms, e.g. in pyridine ligands, or in resonance therewith, e.g. in isocyanide ligands C=N-R or as complexed central atoms the ligands containing nitrogen
  • B01J31/181—Cyclic ligands, including e.g. non-condensed polycyclic ligands, comprising at least one complexing nitrogen atom as ring member, e.g. pyridine
  • B01J31/1815—Cyclic ligands, including e.g. non-condensed polycyclic ligands, comprising at least one complexing nitrogen atom as ring member, e.g. pyridine with more than one complexing nitrogen atom, e.g. bipyridyl, 2-aminopyridine
  • B01J31/182—Cyclic ligands, including e.g. non-condensed polycyclic ligands, comprising at least one complexing nitrogen atom as ring member, e.g. pyridine with more than one complexing nitrogen atom, e.g. bipyridyl, 2-aminopyridine comprising aliphatic or saturated rings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
  • B01J31/18—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes containing nitrogen, phosphorus, arsenic or antimony as complexing atoms, e.g. in pyridine ligands, or in resonance therewith, e.g. in isocyanide ligands C=N-R or as complexed central atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B53/00—Asymmetric syntheses
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
  • C07C29/48—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by oxidation reactions with formation of hydroxy groups
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
  • B01J2531/02—Compositional aspects of complexes used, e.g. polynuclearity
  • B01J2531/0238—Complexes comprising multidentate ligands, i.e. more than 2 ionic or coordinative bonds from the central metal to the ligand, the latter having at least two donor atoms, e.g. N, O, S, P
  • B01J2531/0258—Flexible ligands, e.g. mainly sp3-carbon framework as exemplified by the "tedicyp" ligand, i.e. cis-cis-cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
  • B01J2531/30—Complexes comprising metals of Group III (IIIA or IIIB) as the central metal
  • B01J2531/38—Lanthanides other than lanthanum
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
  • B01J2531/30—Complexes comprising metals of Group III (IIIA or IIIB) as the central metal
  • B01J2531/39—Actinides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
  • B01J2531/70—Complexes comprising metals of Group VII (VIIB) as the central metal
  • B01J2531/72—Manganese
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
  • B01J2531/80—Complexes comprising metals of Group VIII as the central metal
  • B01J2531/84—Metals of the iron group
  • B01J2531/842—Iron

Definitions

• the present invention relates to the field of oxidation catalysts and catalysis. More particularly, the invention relates to the field of catalysts useful for the oxidation of olefins, in particular, the enantioselective oxidation of olefins.
• chemoselectivity is of paramount significance both in chemistry and in biology. Selection in reactions among or between different functional groups, such as alcohols, ketones, aldehydes, carboxylic acids and others is referred to as chemoselectivity.
• Regioselectivity refers to the selection of one orientation, or regioisomer, over any other that could be created or destroyed in a substrate altered by the reaction.
• Stereoselectivity encompasses the concepts of diastereoselectivity (selection among diastereomers, two chemicals that have the same connectivity that are nonsuperimposable nonmirror images) and enantioselectivity (selection between two possible entantiomers, two chemicals that have the same connectivity that are nonsuperimposable mirror images).
• diastereoselectivity selection among diastereomers, two chemicals that have the same connectivity that are nonsuperimposable nonmirror images
• enantioselectivity selection between two possible entantiomers, two chemicals that have the same connectivity that are nonsuperimposable mirror images.
• chemists employ an array of reagents that incorporate almost the entire periodic table; elements are collected from every accessible environment.
• the present invention uses a new oxidatively and hydrolytically robust transition metal complex, containing metals such as iron or manganese, where in its active form the oxo ligand species is reactive in O-atom transfer reactions to organic nucleophiles.
• the system of the present invention also employs a second reaction to increase the electrophilicity of the oxo ligand.
• Attachment of Lewis acidic species usually in the form of positively-charged ions in the immediate vicinity of the metal- oxo moiety of a modified tetradentate ligand delivers the targeted increase in O- electrophilicity and thereby results in effective metallo O-atom transfer agents, as shown schematically in Figure 1 for one embodiment of the catalyst.
• the present invention provides a method of transferring oxygen to at least one oxidizable site in a target compound having a plurality of oxidizable sites or of transferring oxygen to an oxidizable site of a prochiral species.
• Oxidizable refers to any site that will accept an oxygen atom, such as, an olefin or an alkynyl site, or that is subject to another form of oxidation produced by the oxidizing catalyst systems presented hereine.
• Oxidation of prochiral species to produce chiral compounds proceeds similarly except that only one oxidizable site need be present and the catalyst system must be one that possesses' chirality.
• the method comprises adding to a solution containing a target compound having a plurality of oxidizable sites therein, a source of oxygen atoms, a source of a Lewis acid species, most commonly a cationic species, and, a catalyst having the structure
• Z is N or O and at least one and preferably four Zs are N species;
• MO is a transition metal -oxo species ;
• Chi is selected from the group consisting of pyridine, pyrimidine, pyrazine, dicyano-pyrazine, mono- or di-, tri- or tetra- substituted benzene, benzimidazole, benzoquinone, di-imino-substituted benzene, indole, substituted crown derivatives, cryptand ligands, EDTA derivatives, five membered rings and five membered ring derivatives, porphyrin derivatives, metallated pthalocyanine based systems, bipyridyl-based systems, phenanthroline based systems and salen based systems; Ch 2 and Ch 3 each represent a unit joining the adjacent Z atoms comprised of
• Ri, R 2 , R , and R 4 pairwise and cumulatively, are the same or different and each is selected from the group consisting of hydrogen, alkyl, aryl, alkenyl, alkynyl, alkylaryl, cycloalkyl, cycloalkenyl, alkoxy, phenoxy, halogen, fluoroalkyl, perfluoroalkyl, fluoroalkenyl, perfluoroalkenyl, CFkCF and CF 3 , or R], R 2 , R 3 and R.
• Ch_ ⁇ is a unit joining the adjacent Z atoms selected from the group consisting of
• R 5 , R are the same or different linked or nonlinked and are each comprised of hydrogen, ketones, aldehydes, carboxylic acids, esters, ethers, amines, imines, amides, nitro, sulphonyls, sulfates, phosphoryls, phosphates, silyl, siloxanes, alkyl, aryl, alkenyl, alkynyl, alkylaryl, cycloalkyl, cycloalkenyl, alkoxy, phenoxy, halo, CFfeCF 3 or CF 3 , or the paired R substituents of the R 5 , R 6 pair together form a cycloalkyl or a cycloalkenyl ring; and allowing the oxidation reaction to proceed for a period of time sufficient to oxidize the desired oxidizable site in the target compound.
• Lewis acids include cationic, neutral and anionic species.
• cation-catalyst complex as used herein is intended to encompass the use of all such species as the entity that binds to the catalyst and changes its activity and is not limited to cations.
• the metal ions are any Lewis acid species, such as protons, alkali, alkaline earth, rare earth, transition metal or main group metal ions.
• the plurality of oxidizable sites in the target compound differ from each other in relative reactivity and the cation added to the solution is selected to selectively activate the catalyst to oxidize one oxidizable site of the target compound.
• the method of the invention therefore includes the steps of identifying a series of oxidizable sites on the target compound, each oxidizable site in the series having sequential reactivities ranging sequentially from a beginning oxidizable site having the highest relative reactivity of the series of oxidizable sites to an ending oxidizable site having the lowest relative reactivity of the oxidizable sites in the series of sites, adding to the solution a first cation for activating the catalyst to form a first cation-catalyst complex having a first reactivity level sufficient to oxidize a desired first oxidizable site, such that a second oxidizable site in the series of oxidizable sites then has the highest relative reactivity of the oxidizable sites remaining in the series of sites of the target compound.
• the first cation is optionally removed from the solution.
• a second cation for activating the catalyst to form a second cation-catalyst complex is added to the solution, the second cation-catalyst complex having a reactivity level sufficient to oxidize the second oxidizable site on the target compound, and the oxidation reaction proceeds for a period of time sufficient to permit the oxidation of each second oxidizable site on the target compound such that the next oxidizable site in the series of oxidizable sites on the target compound has the highest relative reactivity of the oxidizable sites remaining in the series of sites.
• the second cation is optionally removed from the solution.
• the foregoing steps are repeated by adding cations to the solution, allowing the oxidation to proceed and optionally removing the cation from the solution, each successive cation added to the solution forming a cation-catalyst complex having a progressively higher reactivity to effect the sequential oxidation of the oxidizable sites in the series of oxidizable sites until each ending oxidizable site is oxidized.
• the cations form strong bonds with the secondary site or sites of the catalyst, removal of the cation and the cation-catalyst complex will not be required.
• cation removal will not be necessary.
• the method may further include the enantioselective oxidation of at least one prochiral oxidizable site on a target compound such targeted compounds may have only one oxidizable site.
• the catalyst or cation- catalyst complex used in the enantioselective oxidation includes substituents for making the complex asymmetric such that when reacting with the prochiral oxidizable site of the target compound, the cation-catalyst complex favors the formation of one enantiomer over the other or in cases where the substrate already possesses chirality favors a selection among diastereomeric alternatives.
• the method may alternatively function in kinetic resolution applications in which one enantiomer of a pair in a mixture is selectively winnowed from that mixture.g23
• FIG. 1 is a schematic representation of the catalytic cycle that the switched oxidations of the present invention are believed to follow.
• FIG. 2 is a molecular structure of the compound 1 : an ORTEP drawing with nonhydrogen atoms drawn to encompass 50% of electron density wherein the Mn atom lies 0.579A above the plane towards the oxo atom, and the coordinated oxygen is positioned symmetrically above the manganese. Selected bond lengths [A]: Mn- 0(1), 1.549(3); Mn - N(l), 1.884(4); Mn - N(2), 1.873(3); Mn - N(3), 1.881(3); Mn - N(4), 1.885(3).
• FIGS. 3A and 3B illustrate, in A) the UV/Vis spectra of compound 1 (9.71 x 10 "5 M, 3 mL sample size) wherein aliquots of Li(OSO 2 CF 3 ) in acetonitrile were added (0.06 ⁇ mol in 2 ⁇ L in initial additions); and in B) the mole ratio plot corrected for dilution.
• FIG. 4 represents the infrared spectra (polyethylene film) of compound 1 (light line) and of lithiated compound 1 (heavy line) showing the 15 cm "1 increase in the v(Mn ⁇ 18 O) band associated with lithiation of the switching site.
• the Li + binding induces a substantial drop in donor capacity of the macrocyclic tetraamido-N ligand, a drop that is compensated for by an increase in the binding energy of the oxo ligand.
• FIGS. 5 A and 5B represent, in A) rates of change of the UV/Vis absorption of compound 1 at 396 nm in the presence of triphenylphosphine and different switching ions.
• Normalized observed rate constants experiment number, number of equiv of cation, cation, relative rate ⁇ standard deviation of minimum of three runs: 1, no cation, 0, 1; 2a, 5, Na ⁇ 2.7 ⁇ 0.1; 3a, 5, Ba 2+ , 4.8 ⁇ 0.5; 3b, 60, Ba 2+ , 5.7 ⁇ 0.1 ; 4a, 5, Mg 2+ , 7.0 ⁇ 0.4; 4b, 60, Mg 2+ , 7.2 ⁇ 0.8; 5a, 5, Li + , 13.5 ⁇ 2.0; 6a, 5, Zn 2+ , 24.5 ⁇ 1; 6b, 60, Zn 2+ , 24.1 ⁇ 0.8; 5b, 60 Li + , 25.0 ⁇ 0.5; 2b, 60, Na + , 506.4
• FIG. 7 schematically illustrates the metal insertion, for manganese.
• FIG. 8 is the 1HNMR spectrum of the species, [LMn v ⁇ O] " .
• the low symmetry resulting from the presence of the pyridine-N and the Mn(O) is reflected in the observation of four methyl resonances, cc'dd'.
• FIGS. 9A and B illustrate the UV/Vis study of Na + binding to [LMn v ⁇ O] " for various molar equivalents of Na + , 0.0 (shown by the longer dashed line, — ), 25 (shown by the shorter dashed line, — ), and 60 (shown by the darkest solid line).
• the mole ratio plot indicates that there are two binding processes. One is Na + binding into the switching site and the other binding event is believed to occur at one of the amide oxygens.
• FIGS. 10A, B, C and D illustrate the UV/Vis and IR study of Zn 2+ binding to [LMn v ⁇ O] " for various molar equivalents of Zn 2+ , 0.0 (shown by the longer dashed line, ), 0.23 (shown by the shorter dashed lines, ) and 0.69 (shown by the darkest solid line).
• FIGS. 11A, B, C and D illustrate the UV/Vis study of Mg 2" " binding to [LMn v ⁇ O] " for various molar equivalents of Mg 2+ with 0.0 being shown by longer dashed lines, 0.30 shown by shorter dashed lines and 1.06 shown by the darkest solid line.
• FIGS. 12A and B illustrate the UV/Vis study of Ca 2+ binding to [LMn v ⁇ O] ⁇ for various molar equivalents of Ca .
• FIGS. 13A and B illustrate the UV/Vis study of Ba 2+ binding to [LMn v ⁇ O] " for various molar equivalents of Ba 2+ .
• FIGS. 14A and B illustrate the UV/Vis study of Sc 3+ binding to [LMn v ⁇ O] " for various molar equivalents of Sc 3+ .
• the Sc 3+ exhibits complex binding behavior, however, only one equivalent is required to reach the endpoint.
• FIGS. 15A-F illustrate the O - atom reactivity studies of [LMn v ⁇ O] " and tetramethylethylene monitored by C-NMR; growth on the resonances of the carbon product over time are shown in a progression from light to dark traces.
• the preferred embodiment of the catalyst used in the method of the present invention contributes to the "greening" of chemistry by invoking the principle that reagents should be composed of low toxicity elements.
• the metal is one of the low toxicity elements, i.e., iron or manganese.
• the supporting ligand system is preferably comprised of carbon, hydrogen, nitrogen, oxygen and other biologically common elements. It is preferred that the primary oxidant is one found widely in Nature, such as oxygen or one of its reduced derivatives, especially hydrogen peroxide. This reasoning constitutes a significant environmental case for advancing ligand design to afford nontoxic, long-lived iron and manganese catalysts for activating peroxides and oxygen for a wide range of homogeneous oxidations.
• the catalysts found to be useful for the methods of the present invention have the general structure:
• Z is N or O and at least one Z, and preferably four Zs are N; MO is a transition metal -oxo species ;
• Chi is selected from the group consisting of pyridine, pyrimidine, pyrazine, dicyano-pyrazine, mono- di- tri- or tetra- substituted benzene, benzimidazole, benzoquinone, dimino-substituted benzene, indole, substituted crown derivatives, cryptand ligands, EDTA derivatives, five membered rings and five membered ring derivatives, porphyrin derivatives, metallated pthalocyanine based systems, bipyridyl-based-systems, phenanthroline based systems and salen based systems, in accordance with the representations for such substituents as set forth in Table I herein ; Ch 2 and Ch 3 each represent a unit joining the adjacent Z atoms comprised of
• Ri, R , R 3 , and ⁇ are the same or different and each is selected from the group consisting of alkyl, aryl, alkenyl, alkynyl, alkylaryl, cycloalkyl, cycloalkenyl, alkoxy, phenoxy, halogen, CH 2 CF 3 and CF 3 , or Ri, R 2 , R 3 and R 4 together form a substituted or an unsubstituted benzene ring, or the paired R substituents of the Ri, R 2 or the R 3 , j pairs together form a cycloalkyl or a cycloalkenyl ring; and, Clu is a unit joining the adjacent Z atoms selected from the group consisting of
• R 5 , and R are the same or different, linked or nonlinked, and each is comprised of hydrogen, ketones, aldehydes, carboxylic acids, esters, ethers, amines, imines, amides, nitro, sulphonyls, sulfates, phosphoryls, phosphates, silyl, siloxanes, alkyl, aryl, alkenyl, alkynyl, alkylaryl, cycloalkyl, cycloalkenyl, alkoxy, phenoxy, halo, CF1>CF 3 or CF 3 , or the paired R substituents of the R$, Re pair together form a cycloalkyl or a cycloalkenyl ring.
• a preferred embodiment of the catalyst is the tetraamido ligand shown in
• the catalyst used in the method of the invention contains a bidentate secondary site which in compound 1 is comprised of the pyridine nitrogen and the adjacent amide oxygen.
• the electronic influence of binding a secondary ion is transmitted to the Mn(O) moiety via a combination of ⁇ and ⁇ perturbations.
• Such a binding increases the electrophilicity of the oxo ligand, thereby increasing its O-atom transfer reactivity.
• the secondary binding is referred to herein as a 'switching' event, an event whereby a secondary reaction is arranged in time to cause a primary reaction to proceed to deliver a targeted reactivity and selectivity at an acceptable rate.
• switching processes are used to activate compound 1 such that it performs useful oxidations on convenient time scales.
• the relative reactivity of the catalyst can be controlled.
• the chemo- and regio-selectivity and sequence of oxidation reactions at desired sites in a larger compound having a plurality of possible oxidation sites can be controlled.
• the introduction of chirality at desired prochiral sites can be controlled, by synthetically modifying the environment surrounding the active site of the catalyst to introduce asymmetry or by bringing asymmetry to the cation catalyst complex via groups attached to the switching cation.
• the size and shape of the complex can be altered to have it favor contact with one side of the desired oxidation site, for example, an olefin, in preference to the other side.
• the rate can be controlled by the choice of the secondary ion.
• the successful catalytic O-atom transfer to tetramethylethylene (see Fig. 15) together with the ability to control the rate of the reaction by selective manipulation of the secondary ion demonstrates that the oxidation catalysts of the present invention are useful in the oxidation of a variety of substrates, including olefins.
• the selective oxidation method of the present invention may proceed as follows: the oxo catalyst [LMn v ⁇ O] ⁇ and a source of the desired alkaline, alkaline earth or transition metal cation, main group metalion and a source of oxygen atoms, such as a peroxy compound or oxidant, are mixed at room temperature in a solution containing a solvent and a target compound having a plurality of olefin sites. If necessary to produce a reaction at an acceptable rate, the solution is heated. The reaction produces an oxidation at the most reactive olefin site or sites and any others that the reactivity of the cation-catalyst complex will accommodate.
• the oxo catalyst [LMn v ⁇ O] ⁇ and a source of the desired alkaline, alkaline earth or transition metal cation, main group metalion and a source of oxygen atoms, such as a peroxy compound or oxidant are mixed at room temperature in a solution containing a solvent and
• a series of olefin sites from the most reactive to the least reactive can be oxidized respectively, by catalysis beginning with the cation bound to the secondary binding site of the oxo-tetraamido ligand that yields the least reactive cation-catalyst complex, [LM(O)] " and proceeding to the most reactive cation-catalyst complex.
• a typical sequence for a target compound having a plurality of olefin sites, a, b, c, d, e, f, g, etc., is to add a source of a first cation, one yielding the least reactive cation-catalyst complex, to the reaction mixture described above.
• the cation will bind to the secondary binding site of the oxo catalyst.
• the cation-catalyst complex will initiate the oxidation of the most reactive olefin site, the first olefin site a, on the target compound.
• the reaction will stop and the first cation optionally will be removed, if necessary.
• a source of a second cation will be added to the reaction mixture and will bind to the secondary binding site of the oxo catalyst which will in turn initiate the oxidation of the most reactive remaining olefin site , a second olefin site b, on the target compound, (the most reactive site originally present having been previously oxidized).
• the second cation will be removed, if necessary from the reaction mixture and a third cation will be added to bind to the secondary binding site of the oxo-catalyst whereupon the catalyst will initiate the oxidation of the most reactive remaining olefin site, a third olefin site c, on the target compound.
• the process can continue to effect the sequential oxidation of different olefin sites, d, e, f, g, etc., on the target compound. Sequential reactivity can also be obtained with one cation whereby the temperature is the controlling factor.
• the cation/catalyst complex oxidizes the least reactive site at a temperature chosen so that only this site reacts.
• a temperature can be found where the two mostt reactive sites react selectively compared to the others, etc.
• the foregoing is an example of chemoselectivity.
• one of the olefins or one grouping of olefins will be more reactive than the other olefins or groups of olefins.
• Each olefin or olefin group will differ somewhat in reactivity.
• oxidation at one functional group in preference to oxidation at another functional group can be controlled.
• the reactivity of the oxo-catalyst can also be controlled by changing the metal ion, M, to another transition metal.
• M metal ion
• Iron for example, is vastly more reactive than manganese in these catalyst systems.
• Manganese is preferred for systems where a mild oxidation catalyst is called for.
• the switching catalysts are useful for incorporating asymmetry into prochiral substrates.
• the enantioselectivity with regard to the prochiral sites on a target compound can be controlled by the presence of asymmetry in the cation-complex.
• the oxygen atom transfer site on the catalyst must be able to reach the olefin, or other oxidizable prochiral site of the target compound.
• Chirality can be built into the oxo-catalyst or brought to it via the switching cation and groups attached thereto. By selecting the substituents on the catalyst, the size, shape and chiral character of the catalyst can be controlled. Numerous variations for substituent groups and the manner of making them are disclosed in the Collins et al.
• the catalyst systems of the present invention can also induce chirality by transferring sulfur compounds oxygen atoms from the switching catalyst to an organic or inorganic substrate.
• a prochiral phosphorous compound for example, can be oxidized at phosphorys or sulfur so that chiral species result.
• the pyridine-substituted macrocycle (Compound 1) shown in Figure 1 can be synthesized by an adaptation of the multistep procedure for making macrocyclic tetraamides disclosed in co-pending U. S. Patent Application, Serial No. 08/681,187 of S. Gordon- Wylie et al., cited above and inco ⁇ orated herein.
• the parent complex without the pyridine group was reported in T. J. Collins, R. D. Powell, C. Slebodnick, E. S. Uffelman, J. Am. Chem. Soc. 113, 8419-8425 (1991).
• the synthesis of the tetradentate ligand proceeds generally as follows .
• an amino carboxylic acid preferably an or ⁇ amino carboxylic acid
• a supporting solvent is heated with an activated derivative selected from the group consisting of oxalates and malonates, such as a substituted malonyl dichloride in the presence of a base, to form an intermediate.
• an activated derivative selected from the group consisting of oxalates and malonates, such as a substituted malonyl dichloride in the presence of a base, to form an intermediate.
• a diamide dicarboxyl-containing intermediate is isolated.
• a diamine is added to the intermediate in the presence of a solvent and a coupling agent.
• the diamine is one providing a secondary binding site, such as those selected from the group consisting of pyridine, pyrimidine, pyrazine, dicyano-pyrazine, mono- or di- substituted benzene, benzimidazole, indole, substituted crown derivatives, cryptand ligands, EDTA derivatives, five membered rings and five membered ring derivatives, po ⁇ hyrin derivatives, metallated pthalocyanine based systems, bi-pyridyl based systems, phenanthroline based systems and salen based systems, such as those diamines shown in Table I.
• the coupling agent is preferably a phosphorous halide compound or pivaloyl chloride.
• the resulting mixture is heated and the reaction is allowed to proceed for a period of time sufficient to produce the macrocyclic tetradentate compounds, usually 48-72 hours at reflux when pyridine is the solvent. Typically, stoichiometric amounts of the reactants are used.
• the substituent groups on the amino carboxylic acids, the activated oxalate or malonate derivatives and the diamines may all be selectively varied so that the resulting tetradentate macrocycle can be tailored to specific desired end uses. Variation in the substituents has little or no effect on the synthesis methodology.
• the compound is complexed with a metal ion, preferably a transition metal ion from Groups 6 (Cr, Mo, W), 7 (Mn, Tc, Re), 8 (Fe, Ru, Os), 9 (Co, Rh, Ir), 10 (Ni, Pd, Pt), and 11 (Cu, Ag, Au) of the Periodic Table of the Elements or those having oxidation states of I, II, III, IV, V, VI, VII or VIII. Because the preferred use of the catalyst systems of the present invention is environmentally sound oxidations, those metals that are nontoxic are preferred, with manganese and iron being the most preferred.
• a metal ion preferably a transition metal ion from Groups 6 (Cr, Mo, W), 7 (Mn, Tc, Re), 8 (Fe, Ru, Os), 9 (Co, Rh, Ir), 10 (Ni, Pd, Pt), and 11 (Cu, Ag, Au) of the Periodic Table of the Elements or those having oxidation states of I,
• a ligand metal oxo complex is formed.
• a strong O-atom transfer oxidant preferably a peroxide, such as hydrogen peroxide, t-butyl peroxide, or cumyl peroxide.
• a peroxide such as hydrogen peroxide, t-butyl peroxide, or cumyl peroxide
• Any source of oxygen atoms can be used.
• Z is the metal complexing atom, preferably N;
• X is a functionality resistant to oxidation when the metal complex is in the presence of an oxidizing medium;
• R' and R" are the same or different and each is selected from the group consisting of substituents which are unreactive, form strong bonds intramolecularly within R' and R" and with the cyclic carbon to which they are bound, are sterically hindered and are conformationally hindered such that oxidative degradation of the metal complex is restricted in the presence of an oxidizing medium.
• X is preferably oxygen or NR s , wherein R s is methyl, phenyl, hydroxyl, oxylic, CF 3 and CH 2 CF 3 .
• R' and R" are each preferably hydrogen, methyl, halogen, CF 3 , and if linked, a cycloalkyl such as cyclopentyl, cyclobutyl, cyclohexyl or cyclopropyl.
• R' and R" can be any one of the groups recited for Ch. above or additionally those chosen for R 5 and R ⁇ on page 11. Oxidatively robust oxidation catalysts are described in more detail in the T. Collins et al., U.S. Patent Application, Serial No. 08/681,237 filed July 22, 1996 cited above and inco ⁇ orated herein by reference.
• Manganese insertion into the macrocycle of compound 1 is complicated in that both the primary tetraamide and the secondary site readily bind manganese under basic aprotic conditions. Thus, manganese must be removed from the secondary site after the insertion into the primary site. In the case of manganese, this is achieved by basic aqueous workup conditions. A useful synthesis proceeded as follows.
• Example 1 The ligand (425 mg, 1.05 x 10 "3 mol), was dissolved in dry tetrahydrofuran (THF, 40 mL) under an inert atmosphere, and lithium [bis(trimethylsilylamide)] (6.32 mL of l.OM THF solution, 6.3 x 10 " mol) was added. The mixture was stirred (5 mins) and manganic acetylacetonate, Mn (acac) 3 (557 mg, 1.58 x 10 "3 mol), was then added as an acetonirile solution (10 mL). The reaction mixture was stirred (2 hours) and the solution was then evaporated to dryness in air on a rotary evaporator.
• THF dry tetrahydrofuran
• the solid residue was dissolved in minimal amount of water and filtered to remove the solid residue.
• the filtrate was evaporated to dryness under reduced pressure and the resulting solid, Li[LMn ⁇ ], was dissolved in acetone and filtered.
• the filtrate was treated with excess tert-butylhydroperoxide (TBHP) solution (0.586 mL, 5.25 x 10 mol, 90% TBHP containing 5% tert-butyl alcohol and 5% water).
• TBHP tert-butylhydroperoxide
• Example Set 2 The reversible formation of secondary complexes of compound 1 was monitored in acetonitrile by UV/Vis spectroscopy employing a range of mono-, di-, and trivalent cations.
• the monocationic alkali series, Li + , Na + and K + (as the triflate salts), exhibit a su ⁇ risingly large variation in the binding properties.
• the mole ratio plot for Na + binding shows that there are two binding processes, as evidenced by a first plateau beginning at 8 equivalents of Na + and a second plateau beginning at 47 equivalents. It is believed that the first binding event occurs at the bidentate site and the second binding event occurs at a monodentate amide O-atom.
• the UV/Vis spectrum does not change on addition of K + (up to 60 equiv).
• the UV/Vis changes nonisosbestically on addition of Ba 2+ (Figure 13) in such a manner as to suggest that more than one compound 1 anion can bind to Ba 2+ ; Ba 2+ binding is strong with the mole ratio plot indicating that the endpoint is reached at 1.3 equivalents of the Ba 2+ .
• the susceptibility of the manganyl moiety of the compound 1 system to secondary ion perturbation can be illustrated by the effect of Lf binding on the v(Mn ⁇ ) band in the IR spectrum.
• the ⁇ -labeled manganyl was examined; this was produced by stirring [Et 4 N] [compound 1] in a mixture of CH 3 CN/H 2 18 O (1:1; 98% 18 O) for three weeks at room temperature.
• the v(Mn ⁇ 18 O) band for the Li + free and Li + bound species are shown in Figure 4; v(Mn ⁇ O) shifts from 939 cm " in the parent complex to 954 cm " 1 in the Li + complexed species.
• Example Set 4 The effects of the different switching ions on reactivity were first examined by studying a proof of concept oxidation, namely the oxidation of triphenylphosphine to triphenylphosphine oxide.
• the reactions with different switching ions were monitored by UV/Vis spectroscopy at 15 °C in acetonitrile under air employing one equivalent of compound 1 and 100 equivalents of triphenylphosphine.
• Example 5 A mixture of [Ph P] compound 1 (1 equiv), ZnTf 2 (4.5 equiv), 2,3-dimethyl- 2-butene (tetramethylethylene, 132 equiv), and TBHP (90%, 266 equiv) in acetronitrile-d 3 was monitored at 50°C via 13 C spectroscopy until all of the olefin had been consumed (48 hr). The only observable product was 2,3-dimethylbut-3-en- 2-ol (>98%); the reaction was performed in triplicate.
• the product solution was also analyzed by GC/MS which confirmed the presence of 2,3-dimethylbut-3-en-2-ol as the only olefin-derived product.
• the product, the generated tert-butanol, and the remaining TBHP had the same relative abundance indicating a very clean stoichiometric and selective reaction.
• a ligand system can be designed for organizing in sequence and reaction site more than one oxidation reaction to achieve a targeted reactivity and selectivity.
• the ligand systems of the present invention are significantly resistant to oxidative decomposition such that they provide very long-lived and reusable catalysts.
• Rj H, Alkyl, Aryl, Alkenyl, Halo
• R 2 H, Alkyl, Aryl, Alkenyl, Halo
• Switching can be accomplished via metallation of the porphyrin, v . i.a_. oxidation state change of the free base porphyrin or the metallated porphyrin, via change in the axial ligation of the metal porphyrin, optically etc. 32
• Switching can be accomplished via metallation of the free base pthalocyanine, oxidation state change of the metallated pthalocyanine, axial ligation of the metal pthalocyanine complex, optically etc. TABLE T Continued

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