Diketone-Enabled Regioselective Cobalt-Catalyzed C–H/N–H Activation with Alkyl Alkynes

Annulation of alkynes with C-H/N-H bonds is a green and efficient method for constructing lactams. Controlling the regioselectivity of unsymmetric alkynes, especially alkyl-substituted alkynes, remains challenging. Herein, we report a regioselective annulation of C-H and N-H bonds with alkyl alkynes catalyzed by cobalt using diketone. This transformation has excellent functional group tolerance and a wide substrate scope. Mechanistic experiments demonstrate that the 2,2,6,6-tetramethyl-3,5-heptanedione (TMHD) ligand plays a crucial role in this reaction.