The cyclopropanation of olefins with alkyl diazoacetates were carried out by copper complexes of Schiff bases, derived from chitosan and substituted salicylaldehydes, as the catalysts. The catalysts showed high activity and up to 56% e.e. was achieved under optimal conditions; moreover, the catalysts could be easily recovered and reused after the reaction. (C) 2003 Elsevier B.V. All rights reserved.