After studying the cyclopropanation reaction by using chiral unsaturated carbonyls and chiral ylide, we studied the combined reaction of chiral unsaturated carbonyls (2a-2l) with chiral ylide 3c. Steric hinderance play major rule than stereoselectivity in this type of reactions. Chiral olefin 2a on reaction with chiral ylide 3c, in various solvents and found that acetonitrile at room temperature is the best choice and gives good chemical yield and diastereoselectivity (Fig. ). In the class of reaction only olefin and beta-ester are effective. In olefin, the products 25b stereoselectivity is increases to 93% in contrast to beta-ester 26b, where its stereo selectivity decreases. Surprisingly, the beta-alkyl is ineffective and as expected substituted or disubstituted substrate are unreactive due to steric hinderance. Mechanism: From this structure it may be inferred that the transition state for this cyclopropanation involved a non-chelate model in which the bond dipole carbonyl group of chiral camphorpyrazolidinone and the attacking carbon are oriented in opposite direction.