Palladium-catalyzed α-ketocyclopropanation of norbornenes with propargyl acetates.

Propargyl acetates reacted with norbornene in the presence of a catalytic amount of tetrakis(tripheylphosphine)palladium to give cyclopropyl ketones. The reaction proceeded with high stereoselectivity, affording a single stereoisomer. The reaction of various substituted norbornenes gave the corresponding cyclopropanes in moderate to good yields.