Process for preparation of optically active .alpha.-bromo and .alpha.-chlorocarboxylic compounds

Abstract

Optically active .alpha.-bromo- or .alpha.-chlorocarboxylic compounds of the formula ##STR1## wherein X is bromine or chlorine; M is hydrogen, NR.sub.4.sup.+1 or a cation of an alkali or alkaline earth metal; R.sup.1 is hydrogen or lower alkyl; n is 0 or 1; R is hydrogen, C.sub.1 -C.sub.20 alkyl, or C.sub.1 -C.sub.20 alkyl substituted in the terminal position with --NR.sup.2.sub.2, --COOR.sup.2, --OR.sup.3, a free or protected --CHO group or a ring A; R.sup.2 is hydrogen or a lower alkyl; R.sup.3 is hydrogen or a protecting group; ring A is an unsubstituted or substituted ring; and * is a center of chirality, are prepared by enantioselectively hydrogenating, in the presence of a ruthenium complex of an optically active diphosphine ligand, a (Z)-.alpha.,.beta.-unsaturated compound of the general formula ##STR2## wherein R, n, X and M are as defined above.

Dependencies are inferred from the claim text.