The Development of a Palladium-Catalyzed Tandem Addition/Cyclization for the Construction of Indole Skeletons

A palladium-catalyzed tandem addition/cyclization of 2-(2-aminoaryl)­acetonitriles with arylboronic acids has been developed for the first time, achieving a new strategy for direct construction of indole skeletons. This system shows good functional group tolerance and remarkable chemoselectivity. In particular, the halogen (e.g., bromo and iodo) substituents are amenable to further synthetic elaborations thereby broadening the diversity of the products. Preliminary mechanistic experiments indicate that this transformation involves sequential nucleophilic addition followed by an intramolecular cyclization.