Chiral ruthenium porphyrin-catalyzed asymmetric cyclopropanation of 1,3-dienes with tert-butyl 2-cyano-2-diazoacetate as the carbene source

With the chiral ruthenium porphyrin complex ( S , R )-cmcpor-RuCO as a catalyst and tert -butyl 2-cyano-2-diazoacetate as the carbene source, a panel of substituted vinylcyclopropanes is readily prepared in good product yields and high enantioselectivity.