Palladium-catalyzed C-H activation of anisole with electron-deficient auxiliary ligands: a mechanistic investigation.

Palladium-catalyzed selective C-H activation-functionalization has shown its significance in organic transformations. Recently, Yu et al. reported a palladium-norbornene co-catalyzed meta-selective arylation of electron-rich arenes. Although the experimentally observed site-selectivity has been successfully explained by the computational work of Dongju Zhang and co-workers, some important experimental factors, such as the ligand choice and narrow substrate scope, remain unrationalized. In contrast to what has been suggested by Dongju Zhang, we proposed the palladium-silver dinuclear species as reactive intermediates in this work. The substituent effect was estimated to unravel the e-CMD nature of the rate-determining C-H activation step. Based on this realization, the experimentally observed substrate scope and ligand choice have also been rationalized.