Asymmetric Michael addition reactions using a chiral La-Na aminodiolate catalyst

(R,R)-(+)-2-[Benzyl-(2-hydroxy-2-phenylethyl)amino]-1-phenylethanol 1 is used as a chiral ligand in the synthesis of an optically active lanthanum-sodium amino diol complex LS-1. This heterobimetallic catalyst is quite effective its an asymmetric catalyst for various Michael addition reactions, H-1 NMR Study indicates the co-ordination of enone to the central lanthanum atom in LS-1. The reaction conditions were optimized and the adducts were obtained in high yield with moderate to high enantiomeric excess under extremely mild conditions. (C) 2002 Elsevier Science Ltd. All rights reserved.