Construction of Spirolactams by Unexpected Oxidative Cyclization of Alkenyl Diynes via Copper Catalysis.

A copper-catalyzed oxidative cyclization of alkenyl N -propargyl ynamides is described. This protocol enables the practical synthesis of diverse spirocyclic γ-lactams bearing an exocyclic double bond with generally high Z / E selectivity in moderate to good yields. Importantly, this copper-catalyzed oxidative cyclization demonstrates a distinctive selectivity in comparison with the related gold catalysis.