Method of enantioselectively catalyzing a reaction

a catalytic reaction and selective catalytic technology, applied in the field of catalytic methods, can solve the problems of low to moderate reported enantiomeric excesses of chiral copper catalysts, low stereoselectivities, and low product yield of tri-substituted olefins

Inactive Publication Date: 2006-01-24
RES CORP TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0019]The cyclopropanation aspect of the invention, includes the steps of providing an olefin and a carbene precursor. Either the olefin or the carbene precursor should be prochiral. These are reacted in the presence of the catalysts described above under such conditions sufficient to effect the cyclopropanation. The olefin and the carbene precursor may be on the same molecule to thereby effect intramolecular cyclopropanation.
[0020]The carbene insertion aspect of the invention includes the steps of providing a compound with either a carbon-hydrogen, a silicon-hydrogen, a oxygen-hydrogen, or a nitrogen-hydrogen bond and a carbene precursor. Either the compound or the carbene precursor should be prochiral. These are reacted in the presence of the catalysts described above under such conditions sufficient to effect the insertion. The carbene precursor may be on the same molecule to thereby effect intramolecular insertion.
[0021]The hydrogenation, hydroboration, and hydrosilation aspects of the invention, includes the steps of providing either a hydrogen molecule, a borohydride, or a silicon hydride, and a prochiral compound with either a carbon-carbon or a carbon-oxygen double bond. These are reacted in the presence of the catalysts described above under such conditions sufficient to effect the desired addition reaction.
[0022]The ylide formation aspect of the invention, includes the steps of providing a prochiral diazo compound with a hetero atom containing compound. This compound is reacted in the presence of the catalysts described above under such conditions sufficient to effect the metal stabilized ylide formation.

Problems solved by technology

However, these chiral copper catalysts have only low to moderate reported enantiomeric excesses in cyclopropanation reactions.
Although cyclopropane yields are ordinarily high, stereoselectivities are reportedly low.
However, di- and tri-substituted olefins give low product yields.

Method used

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  • Method of enantioselectively catalyzing a reaction
  • Method of enantioselectively catalyzing a reaction
  • Method of enantioselectively catalyzing a reaction

Examples

Experimental program
Comparison scheme
Effect test

example 1

Preparation of catalyst Dirhodium(II) Tetrakis[(S)-(−)-4-benzyl-2-oxazolidinone](Rh2[4S-BNOX]4) (See FIG. 5b)

[0095]Rhodium(II) acetate (0.497 g, 1.12 mmol), prepared from rhodium trichloride according to the literature procedure (G. A. Rampel et al., Inorganic Synthesis. 13, 90 (1972)), and (S)-(−)-4-benzyl-2-oxazolidinone (2.40 g, 13.6 mmol) obtained from the Aldrich Chemical Company (29,464-0), in 50 mL of anhydrous chlorobenzene was refluxed under nitrogen in a Soxhlet extraction apparatus. The thimble was charged with a 3:1 mixture of sodium carbonate and sand which had been dried at 110° C. for 3 h, and a new thimble containing the sodium carbonate-sand mixture was introduced after refluxing for 24 h. After 49 h, as evidenced by HPLC analysis on a u-Bondapak-CN column, the dirhodium composite was >99% Rh2(4S-BNOX)4. Chlorobenzene was removed by distillation, and the resulting purple solid was chromatographed on a silica gel column using acetonitrile hexane (3:97 to 30:70) to se...

example 2

Preparation of catalyst Dirhodium(II) Tetrakis [(R)-(+)-4-benzyl-2-oxazolidinone](Rh2[4R-BNOX]4) (See FIG. 6b)

[0096]Rhodium(II) acetate (0.218g, 0.493 mmol) and (R)-(+)-4-benzyl-2-oxazolidinone (1.770 g, 10.0 mmol), from Fluka Chemical Company, in 50 mL of anhydrous chlorobenzene was refluxed under nitrogen for 39 h in a Soxhlet extraction apparatus according to the procedure in the previous example. Chromatographic separation of the purple solid, obtained after distillation of chlorobenzene, on a silica gel column, as previously described, yielded fractions that by HPLC analyses were >99.5% Rh2(4R-BNOX)4.

example 3

Preparation of catalyst dirhodium(II) tetrakis[(4S)-(−)-4-isopropyl-2-oxazolidinone](Rh2[4R-IPOX]4) (See FIG. 6a)

[0097]The subject catalyst was made in a procedure similar to that in Example 2.

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Abstract

A chiral catalyst is disclosed together with methods of using it for enantioselective syntheses. The chiral catalyst includes a nucleus with two metal atoms that has four bridging ligands oriented radially to the axis of the nucleus. Each of these ligands includes a two complexing atoms each complexed to one of the metal atoms. At least one of the bridging ligands includes a chiral center which is bonded to one of the complexing atoms. Preferably, all four of the bridging ligands include a chiral center bonded to one of the complexing atoms. The catalyst of the invention has been found to be useful in catalyzing carbenoid transformation reactions such as cyclopropanation.

Description

[0001]The present application is a reissue application of Ser. No. 07 / 950,836, filed Sep. 24, 1992, now U.S. Pat. No. 5,296,595, which is a division, of application Ser. No. 502,139, filed mar.Mar. 29, 1990, now U.S. Pat. No. 5,175,311.STATEMENT OF GOVERNMENT INTEREST[0002]This invention was made with government support under Grant R15-GM-42160-01 awarded by the National Instituted of Health. The government has certain rights in the invention.BACKGROUND OF THE INVENTION[0003]The present invention relates to the field of catalysts. More particularly, the invention relates to catalysts which are useful in enantioselective syntheses.[0004]In recent years, catalytic transformations of organic diazo compounds have been used as highly versatile synthetic methods. Efficient procedures for the formation of carbon-carbon bonds by cyclopropanation, dipolar addition, carbon-hydrogen insertion, aromatic substitution reactions, and ylid generation / rearrangement with allylamines, allyl sulfides,...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C07D205/08C07D207/26C07D207/33C07F7/08B01J31/22B01J31/16B01J31/18C07B53/00C07C51/36C07C55/02C07C67/31C07C67/343C07C67/347C07D207/16C07D263/04C07D307/33C07F7/10C07F7/18C07F15/00
CPCB01J31/16B01J31/181B01J31/2243B01J2231/325B01J2531/0208B01J2531/822C07C67/347C07F15/0013C07F15/008
Inventor DOYLE, MICHAEL P.
Owner RES CORP TECH INC
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