Annulation of α,β-Unsaturated Imines and Alkynes via Cobalt-Catalyzed Olefinic C-H Activation

A cobalt-triarylphosphine catalyst promotes an annulation reaction of an alpha,beta-unsaturated imine and an internal alkyne to afford a polysubstituted dihydropyridine derivative in good yield under mild conditions. The reaction likely involves alkenylation of the olefinic C-H bond via cobalt-mediated nitrogen-assisted C-H activation followed by facile 6 pi electrocyclization of the resulting azatriene intermediate.