Facile benzo-ring construction via palladium-catalyzed functionalization of unactivated sp3 C-H bonds under mild reaction conditions.

A practical synthetic method for the annulation of benzo-rings by the intramolecular coupling of an aryl iodide and a methylene C-H bond is described. The palladium-catalyzed C-H functionalization is directed by an aminoquinoline carboxamide group, which can be easily installed and removed. High yields and broad substrate scope were achieved. An additive of ortho-phenyl benzoic acid, identified from a systematic screening, functions as a critical ligand for the catalytic process under mild condition, even at near room temperature.