Patent ID: 7973198

Claim:
A process for preparing optically active carbonyl compounds by asymmetrically hydrogenating α,β-unsaturated carbonyl compounds in the presence of optically active transition metal catalysts which are soluble in the reaction mixture and have at least one carbon monoxide ligand, the optically active catalyst which has at least one carbon monoxide ligand and is to be used in each case being prepared by pretreating a catalyst precursor with a gas mixture comprising carbon monoxide and hydrogen and the asymmetric hydrogenation being performed in the presence of carbon monoxide supplied additionally to the reaction mixture, which comprises the consecutive steps of a) performing the pretreatment of the catalyst precursor with a gas mixture comprising from 30 to 70% by volume of carbon monoxide, from 30 to 70% by volume of hydrogen and from 0 to 5% by volume of further gases, the proportions by volume mentioned adding up to 100% by volume, at a pressure of from 50 to 90 bar, b) removing excess carbon monoxide from the catalyst thus obtained before use in the asymmetric hydrogenation by decompressing the catalyst pretreated in step a) to a pressure in the range of from 1 to 3 bar, and c) performing the asymmetric hydrogenation in the presence of hydrogen with a carbon monoxide content of from 100 to 1200 ppm, wherein said process is performed continuously, and wherein the reaction product is removed from the reaction mixture and the remaining catalyst is reused after preformation according to step a).