A new ruthenium-catalyzed cyclopropanation of alkenes using propargylic acetates as a precursor of vinylcarbenoids

[RuCl2(CO)3]2 catalyzes intermolecular cyclopropanation of various alkenes with propargylic acetates. The key intermediate of this reaction is a vinylcarbene complex generated from propargylic acetate and the ruthenium complex.