Rapid Access to Functionalized gamma-Lactams through Copper-Catalyzed Oxidative Cyclization of Diynes

An efficient copper-catalyzed oxidative cyclization of diynes is described. A range of functionalized gamma-lactams can be readily constructed by using this protocol. This copper-catalyzed oxidative process proceeds through an alkyne oxidation, carbene/alkyne metathesis, and donor-donor carbene oxidation sequence. The use of readily available substrates, high flexibility, a simple procedure, and mild reaction conditions render the procedure a viable alternative for the preparation of functionalized gamma-lactams.