α,β-Epoxy Vinyl Triflates in Pd-Catalyzed Reactions

Reactions of steroidal α,β-epoxy vinyl triflates in Pd-catalyzed reactions are described. Oxidative insertion of Pd⁰ into the C−O bond, giving vinylpalladium 12, is faster than formation of the π-allyl derivative from the vinyl epoxide. Although 12 can be trapped under certain conditions, it eventually rearranges to palladium alkoxide 14, which is in equilibrium with 15 and/or 10.