Synthesis of 3-(Diarylmethylenyl)oxindole by a Palladium-Catalyzed Domino Carbopalladation/C−H Activation/C−C Bond-Forming Process

A highly efficient palladium-catalyzed synthesis of unsymmetrically substituted 3-(diarylmethylenyl)indolinones from readily accessible starting materials is developed. The domino reaction involves a sequence of intermolecular carbopalladation, C−H activation, and C−C bond formation. A plausible mechanistic pathway for the reaction is discussed on the basis of the kinetic isotope effect [KH/KD (intermolecular) = 1, KH/KD (intramolecular) = 2.7] as well as the electronic effect.