Palladium-Catalyzed C-H Amination/[2 + 3] or [2 + 4] Cyclization via C(sp or sp)-H Activation.

This report describes a palladium-catalyzed Catellani reaction consisting of amination/[2 + 3] or [2 + 4] cyclization via a carboxylate ligand-exchange strategy. This method effectively activates -substituents that avoid a second C-H palladation. The scope of substrates was broad, -methyl-substituted iodoarenes were applied to the reaction smoothly, and -phenyl-substituted iodoarenes can also be obtained by this method. In terms of mechanism, density functional theory calculations proved the sequence of the key five-membered aryl-norbornene-palladacycle intermediate formation and C(sp or sp)-H activation.