Coupling of fischer carbene complexes with alkynylstyrene oxides : Synthesis of benzoxepinones in competition with internal oxygen atom transfer

The coupling of Fischer carbene complexes with conjugated enyne epoxides has been examined. The reaction proceeds by carbene-alkyne coupling to afford an epoxyvinylcarbene complex, which then undergoes CO insertion and cyclization to afford a benzoxepinone or intramolecular oxygen atom transfer to afford a dienone derivative.