Palladium(II)-Catalyzed Coupling of Electron-Deficient Arenes via C-H Activation

Homocoupling and cross-coupling of electron-deficient arenes, including nitrobenzene, (trifluoromethyl)benzene, ethyl benzoate, etc., have been developed to afford biaryls using a catalytic system of Pd(OAc)(2)/trifluoroacetic acid (TFA)/O-2 or K2S2O8. The crucial step is to tune the concentrations of arenes and the loading of TFA carefully to enhance the reaction rates and the selectivity of these couplings involving dual C-H activation.