FeCl₃-Catalyzed Multifunctional LMCT and HAT for Synthesis of Benzo[c]Coumarins from 2-Methyl-1,1′-Biaryls at Ambient Temperature

In this study, we report FeCl₃-catalyzed multifunctional ligand-to-metal charge transfer (LMCT) and hydrogen atom transfer (HAT) for the synthesis of benzo[c]coumarins from 2-methyl-1,1′-biaryls. This catalytic system is straightforward, only using FeCl₃·6H₂O as the catalyst and air as the oxidant under visible-light irradiation at ambient temperature. Mechanistic studies indicate that multifunctional LMCT and HAT processes generate chlorine radicals and aryl carboxyl radicals, which are key active species that facilitate the smooth transformation.