Copper-Mediated Tandem Oxidative C(sp²)–H/C(sp)–H Alkynylation and Annulation of Arenes with Terminal Alkynes

The copper-mediated tandem oxidative C­(sp2)–H/C­(sp)–H cross-coupling and intramolecular annulation of arenes with terminal alkynes has been developed, which offers a highly efficient approach to the 3-methyleneisoindolin-1-one scaffold. In this oxidative coupling process, Cu­(OAc)2 acts as both the promoter and the terminal oxidant. This protocol features a wide substrate scope; high functional group tolerance; exclusive chemo-, regio-, and stereoselectivity; and simple, easily available, and inexpensive reaction system. The transformation has demonstrated for the first time that Cu­(OAc)2 can be renewable after undergoing an oxidative reaction.