Nickel-Catalyzed Cycloaddition of o-Arylcarboxybenzonitriles and Alkynes via Cleavage of Two Carbon–Carbon σ Bonds

An intermolecular cycloaddition reaction has been developed, where o-arylcarboxybenzonitriles react with alkynes to afford coumarins in the presence of Ni(0)/P(CH(2)Ph)(3)/MAD as a catalyst. The reaction process displays an unusual mechanistic feature-the cleavage of two independent C-CN and C-CO bonds.