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

An intermolecular cycloaddition reaction has been developed, where <i>o</i>-arylcarboxybenzonitriles react with alkynes to afford coumarins in the presence of Ni(0)/P(CH₂Ph)₃/MAD as a catalyst. The reaction process displays an unusual mechanistic featurethe cleavage of two independent C–CN and C–CO bonds.