Cp*Co(III)-Catalyzed C(sp3)-H Bond Activation: A Highly Stereoselective and Regioselective Alkenylation of 8-Methylquinoline with Alkynes

Efficient, atom-economical, highly regioselective C(sp(3))-H bond alkenylation of 8-methylquinoline catalyzed by (Cp*)Co(III) is reported. A well-defined, air stable, molecular cobalt catalyst, Cp*Co(III), is employed for the first time in C(sp(3))-H bond activation. The developed methodology is broadly applicable and tolerates a variety of functional groups, under mild conditions. Experimental and density functional theory (DFT) results suggest that the initial cyclometalation was occurred via an external-base-assisted concerted metalation deprotonation pathway.