Asymmetric cyclopropanation catalyzed by copper-Schiff's base complexes

The asymmetric cyclopropanation of styrene with alkyl diazoacetate were per formed with copper complexes of Schiff bases, derived from substituted sali cylaldehydes and a new chiral amino alcohol, as the catalysts. The electron ic and steric properties, as well as the position of those substituents sho w obvious effects on the enantioselectivities, and ee higher than 98% were achieved under optimal conditions. (C) 2001 Elsevier Science B.V. All right s reserved.