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.