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 K 2 S 2 O 8 . 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.