Cobalt-Catalyzed Regioselective Direct C-4 Alkenylation of 3-Acetylindole with Michael Acceptors Using a Weakly Coordinating Functional Group.

Herein, we disclosed the first report on the selective C(4)-H functionalization of 3-acetylindole derivatives using first-row transition metal cobalt where an acetyl group is acting as a weakly coordinating directing group. Selective C(4)-H functionalization has been achieved using diverse Michael acceptors (acrylate and maleimide) simply by switching the additive from copper acetate to silver carbonate. Further the formation of a cobaltacycle intermediate was also detected through HRMS for mechanistic insight.