Diastereoselective Cyclopropanation by Using Camphorpyrazolidinone Derived α,β-Unsaturated Amides and Ylide

<p><b>Abstract:</b> High to moderate diastereoselectivity and high chemical yield are observed in the Michael addition of ylide and chiral camphorpyrazolidinone ylide to an optically pure a,b-unsaturated carboxylic acid derivatives derived from a chiral camphorpyrazolidinone and a,b-unsaturated carbonyl respectively. A novel route to the asymmetric synthesis of cyclopropanation derivatives is described.</p>