Selective Synthesis of Indoles by Cobalt(III)-Catalyzed C-H/N-O Functionalization with Nitrones

The redox-neutral annulation of alkynes by differently decorated nitrones set the stage for a step economical access to indoles with ample substrate scope. The redox-neutral C-H/N-O functionalization process proceeded through kinetically relevant C-H activation by carboxylate assistance, and displayed an excellent site- and regio-selectivity with unsymmetrical nitrones and alkynes.