Palladium-Catalyzed Oxidative Annulation of ortho-Alkenylanilines and Allenes: An Access to Benzo[b]azepines.

Palladium-catalyzed oxidative annulation of ortho-alkenylanilines and allenes to constitute valuable, but synthetically challenging, benzo[b]azepines has been developed. The procedure, involving the cleavage of the terminal C(sp2)-H bond of the vinyl moiety and the participation of allenes as two-carbon cycloaddition partner, is attractive in terms of assembly efficiency and environmental friendliness. The transformation features mild reaction conditions and good functional group tolerance, resulting in a variety of benzo[b]azepines in good to excellent yields.