Patent ID: 6921822

Claim:
Process for preparing stereoisomerically enriched 4-aryl-4-hydroxybutanoic acid derivatives, comprising reacting a) compounds of the formula (I) Aryl-CO—CH 2 CH 2 W (I) where Aryl is a mono-, bi or tricyclic aromatic radical having a total of 5 to 18 ring atoms, each cycle containing no, one, two or three ring atoms selected from the group of oxygen, sulphur and nitrogen, and the mono-, bi- or tricyclic aromatic radical being optionally mono or polysubstituted and W is C(O)YR 1 n where Y is oxygen and n=1 or Y is nitrogen and n=2, or W is CN and R 1 is in each case independently hydrogen, C 1 -C 20 -alkyl, C 4 -C 14 -aryl or C 5 -C 15 -arylalkyl or, in the case that Y is nitrogen, both R 1 radicals together are C 3 -C 12 -alkylene, b) in the presence of a ruthenium-containing catalyst and c) in the presence of at least one amine which is present at least partly in protonated form, d) with formic acid, formates or mixtures thereof.