We have found recently that unsaturated carbonyl camphor pyrazolidinone, an efficient chiral auxiliary that allows its use for Aziridination and Epoxidation . Now we describe here an approach to asymmetric cyclopropanation involving the use of optically pure -unsaturated carboxylic acid derivatives derived from a chiral camphorpyrazolidinone as a Michael accepter of ethyl (dimethylsulfuranylidene) acetate.