METHOD FOR ASYMMETRICLY HYDRATING (ALPHA) KETOCARBONYL COMPOUNDS TO OPTICALLY ACTIVE (ALPHA) HYDROXYCARBONYL COMPOUNDS

摘要

The process is aimed at the asymmetric hydrogenation of alpha -ketocarbonyl compounds, in particular alpha -ketolactones, to give the corresponding optically active alpha -hydroxycarbonyl compounds in the presence of platinum metal diphosphine complexes as catalyst and is characterised by the use of chiral iridium complexes containing an optically active 1,2-diphosphine ligand (1,2-DP) of the general formulae …IMAGE… and a cocatalyst from the group of cyclic dicarboximides, preferably succinimide. …??By using cationic or neutral Ir complexes of the formula [Ir(en)2(1,2-DP]+A- or [Ir(Z)(en)2(1,2-DP)] and succinimide in a molar ratio of 1:1 to 1:50, alpha -ketopantolactone can be hydrogenated with a high optical yield to give (R)-(-)-pantolactone.