Pd-catalyzed C–H bond activation of benzene in the CO2-expanded solvent

Abstract

Abstract In the CO 2 -expanded trifluoroacetic acid, the catalytic activation and functionalization of the C–H bond in benzene to synthesize biphenyl and phenol was investigated by using palladium catalyst and dioxygen. It was found that an extra 40% improvement of catalytic efficiency could be achieved by charging 30 atm of CO 2 . Meanwhile, the presence of the small amount of water would apparently promote the catalytic oxidation. The solvent and substrate isotope effect were also investigated to provide the mechanistic information.