Process for the preparation of optically active aliphatic hydroxycarboxylic acids
US5198569A · kind A · utility
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Key dates
| Filing date | Sep 11, 1991 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Sep 11, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C67/31
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The asymmetric hydrogenation of aliphatic .alpha.-keto esters in the presence of rhodium catalysts which contain as chiral ligand a diphosphine of formula IV EQU (R.sub.3).sub.2 P--Q--P(R.sub.3)hd 2 (IV) wherein R.sub.3 is phenyl, C.sub.1 -C.sub.6 alkylphenyl or C.sub.1 -C.sub.6 alkoxyphenyl, and Q is [2,2,1]-bicyloheptan-1,2-ylene or [2,2,1]-bicyclohept-4,5-en-1,2-ylene, gives the corresponding (R)- or(S)-.alpha.-hydroxycarboxylic acid esters in high rates of chemical conversion and in high enantiomer excesses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.