Asymmetric Darzens condensation on chiral h6-Cr(CO)3 complexed benzaldehydes

Enantioselective Darzens condensation was achieved from optically active (o-substituted benzaldehyde)tricarbonylchromium complexes. The enantiomeric excesses were very high with (2-methoxy- and 2- chlorobenzaldehyde)tricarbonylchromium, and the corresponding epoxides obtained were nearly optically pure.