Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/347—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups
  • C07C51/36—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups by hydrogenation of carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F17/00—Metallocenes
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B53/00—Asymmetric syntheses
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F17/00—Metallocenes
  • C07F17/02—Metallocenes of metals of Groups 8, 9 or 10 of the Periodic Table
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F19/00—Metal compounds according to more than one of main groups C07F1/00 - C07F17/00

Definitions

• This invention relates to novel chiral metallocene-based phosphine ligands and methods for their preparation.
• this invention relates to metal-ligand complexes that can be used as catalysts or precatalysts for asymmetric transformation reactions to generate products of high enantiomeric excess.
• structured arsines are also within the scope of this invention.
• diphosphine ligands exhibit chirality only at the phosphorus atoms:
• FerroTANE chiral 1 ,1'-bis(phosphetano) ferrocenes
• Mezzetti 18 and van Leeuwen 19 have independently reported P-chiral ferrocenyl bisphosphines 4a and 4b. These two ligands have shown excellent enantioselectivities (up to 99% ee) for asymmetric hydrogenation of ⁇ - dehydroamino acid derivatives.
• Zhang has reported a 1 ,1'-bis(Phospholanyl) ferrocene ligand 5 with ketal substitutes at the 3 and 4 positions. 20
• the ligand has shown excellent enantioselectivities in hydrogenation of ⁇ -dehydroamino acid derivatives.
• the ketal groups of the ligand are important for achieving the high enantioselectivity, since the corresponding ligand without ketal groups only provides moderate ee's.
• Zhang has also developed a 1 ,1'-bis(dinaphthophosphepinyl) ferrocene ligand, f-binaphane, which has been successfully applied in the Ir-catalyzed hydrogenation of acyclic aryl imines.
• Reetz has developed a binaphthol-derived ferrocene-based bisphosphonite ligand 6 22 , which has shown excellent reactivities and enantioselectivities in Rh- catalyzed hydrogenation of itaconates and ⁇ -dehydroamino acid derivatives.
• Another class of known ligands exhibits both planar and phosphorus chirality:
• Van Leeuwen has reported ferrocene-based bisphosphines combining planar and phosphorus chirality 7a and 7b 23 . These two ligands have shown excellent enantioselectivities (up to 99% ee) for asymmetric allylic alkylations.
• a metallocene-based phosphine or arsine ligand for use in enantioselective catalysis having the Formula:
• M is a metal
• Z is P or Ar
• L is a suitable linker
• R 1 is selected from substituted and unsubstituted, branched- and straight-chain alkyl, alkoxy, alkylamino, substituted and unsubstituted cycloalkyl, substituted and unsubstituted cycloalkoxy, substituted and unsubstituted cycloalkylamino, substituted and unsubstituted carbocyclic aryl, substituted and unsubstituted carbocyclic aryloxy, substituted and unsubstituted heteroaryl, substituted and unsubstituted heteroaryloxy, substituted and unsubstituted carbocyclic arylamino and substituted and unsubstituted heteroarylamino, wherein the or each heteroatom is independently selected from sulphur, nitrogen, and oxygen;
• X* is selected from:
• R, R 2 and R 3 are independently selected from substituted and unsubstituted, branched- and straight-chain alkyl, substituted and unsubstituted cycloalkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaryl wherein the or each heteroatom is independently selected from sulphur, nitrogen, and oxygen.
• the R 2 and R 3 groups may be substituted by each other, forming together an optionally substituted hetero-ring system.
• M is Fe, although Ru may be another preferred M.
• L preferably comprises a difunctional moiety having the capability at each functionality to bind to phosphorus or arsenic, as the case may be.
• the linker (L) will be derived from a difunctional compound, in particular a compound having at least two functional groups capable of binding to phosphorus or arsenic, as the case may be.
• the difunctional compound may conveniently comprise a compound which can be di-lithiated or reacted to form a di-Grignard reagent, or otherwise treated, to form a dianionic reactive species which can then be combined directly with phosphorus or arsenic, in a diastereoselective manner to form a chiral phosphorus or arsenic as the case may be.
• a first anionic component of the dianionic reactive species may combine with a phosphorus (or arsenic) substituent in a first ligand precusor of the ligand according to the invention
• a second anionic component of the dianionic reactive species may combine again in a diastereoselective manner with a phosphorus (or arsenic) substituent in a second ligand precursor of the ligand again to form a chiral phosphorus (or arsenic) centre according to the invention (the first and second ligand precursors being the same as each other) to connect the first and second ligand precursors together via the linker.
• a leaving group such as a halide will be provided on the phosphorus (or arsenic) substituents of the first and second ligand precursors, which leaving group departs on combination of the anionic component with the phosphorus (or arsenic) substituent.
• the following scheme is illustrative of this process:
• L may be selected from ferrocene and other metallocenes, diphenyl ethers, xanthenes, 2,3-benzothiophene, 1 ,2-benzene, succinimides, cyclic anhydides and many others.
• dianionic linkers may be made from a corresponding di-halo precursor, eg:
• R' represents any suitable number of any one or more suitable substituents.
• dianionic linkers may be represented as follows:
• R 1 include phenyl, methyl, cyclohexyl and t-butyl groups.
• R 2 and and R 3 include, independently, methyl, ethyl, isopropyl and t- butyl groups. Also, R 2 and R 3 may form, together with the nitrogen to which they are attached, an optionally substituted hetero-ring such as morpholine, pyrollidine, piperidine, and derivatives thereof.
• ligands of the invention are derived from Ugi's amine and one preferred ligand in accordance with the invention (wherein the dianionic linker is ferrocence) may be represented as follows:
• the invention also relates to the enantiomers and diastereomers of the ligands described above.
• Ligands in accordance with the invention may also be represented as follows:
• M, L 1 R 1 and X * are as previously defined, and wherein the phosphorus may if desired be at least partially replaced by arsenic.
• the ligand of the invention exhibits chirality at phosphorus (or arsenic).
• the chiral configuration of the phosphorus (or arsenic) substituents at opposite ends of the linker molecule is the same.
• a transition metal complex comprising a transition metal coordinated to the ligand of the invention.
• the metal is preferably a Group VIb or a Group VIII metal, especially rhodium, ruthenium, iridium, palladium, platinum or nickel.
• L is a linker derived from an organolithium species or Grignard reagent L(G) 2 and wherein X* and R 1 are as previously defined.
• X* and R 1 are as previously defined.
• S P refers to S configuration at phosphorus
• R 0 refers to R configuration at carbon (or other auxiliary)
• S Fe refers to S configuration at the planar chiral element.
• the mixture was then diluted with water (60 ml) and then placed under reduced pressure at 45 °C to remove most of the ethanol and some water.
• the resulting mixture was then diluted with water (60 ml) and then placed under reduced pressure at 45 °C to remove most of the ethanol and some water.
• ligand 3.25 x 10 "3 mM) and the vessel placed under vacuum/Ar cycles. The vessel was then flushed with Argon. A degassed solution of [(COD) 2 Rh]BF 4 in MeOH (5 ml of a 0.64 mM solution) was then added by syringe/needle and a rubber bung placed over the vessel to maintain an inert atmosphere. This mixture was stirred for 10 min to give a clear yellow solution. A degassed solution of starting material in MeOH was then added by syringe/needle while carefully attempting to maintain an inert atmosphere.
• the autoclave was then connected to a Parr 3000 multi-vessel reactor system and then placed under Ar (5 bar) and vented while stirring, this process was repeated 3 times. After the final vent the mixture was placed under H 2 (50 bar) and again vented carefully. The mixture was then placed under H 2 (50 bar), sealed and heated to the desired temperature for the required time. After this time the reaction mixture was cooled and the vessel vented. An aliquot of 0.5-1.0 ml was then taken for analysis.
• the vessel was then sealed and stirring commenced.
• the vessel was then placed under Ar (5 bar) and vented, this process was repeated three times.
• the autoclave was then placed under H 2 (50 bar) and again vented carefully.
• the mixture was then placed under H 2 (50 bar), sealed and heated to 40 0 C for 12 h. After this time
• reaction mixture was cooled and the vessel vented. An aliquot of 0.5-1.0 ml was then taken for analysis. Conversion >98%, e.e >98.5 % (major enantiomer second running peak).
• Ligands containing flexible linker units have been found to be most preferable for the enantioselective hydrogenation of the acid substrates described.

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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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• 2005
  • 2005-01-14 GB GBGB0500702.6A patent/GB0500702D0/en not_active Ceased
• 2006
  • 2006-01-13 CN CN200680004909.8A patent/CN101120010B/zh not_active Expired - Lifetime
  • 2006-01-13 DE DE602006015910T patent/DE602006015910D1/de not_active Expired - Lifetime
  • 2006-01-13 EP EP06700701A patent/EP1844061B1/en not_active Expired - Lifetime
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  • 2006-01-13 CA CA2594893A patent/CA2594893C/en not_active Expired - Lifetime
  • 2006-01-13 WO PCT/GB2006/000114 patent/WO2006075166A1/en not_active Ceased
  • 2006-01-13 AU AU2006205652A patent/AU2006205652B2/en not_active Expired
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