A novel chiral zirconium catalyst for enantioselective aldol and Mannich-type reactions. Catalytic activation of both aldehydes and imines using a similar chiral Lewis acid

A novel zirconium catalyst has been developed for asymmetric aldol reaction of aldehydes with silyl enolates and asymmetric Mannich reactions of imine s with silyl enolates. Similar types of catalysts have been successfully us ed in both reactions, and the desired products were obtained in high yields and high selectivities. For the sense of the chiral induction, reverse ena ntiofacial selectivities were observed between aldol reactions and Mannich reactions. (C) 2001 Elsevier Science Ltd. All rights reserved.