Electrochemical-Oxidation-Promoted Direct N-ortho-Selective Difluoromethylation of Heterocyclic N -Oxides.

An efficient and green electrochemical N-ortho-selective difluoromethylation method of various quinoline and isoquinoline N -oxides has been developed. In this method, sodium difluoromethanesulfinate (HCF 2 SO 2 Na) was used as the source of the difluoromethyl moiety, and various N-ortho-selective difluoromethylation quinoline and isoquinoline N -oxides were obtained in good to excellent yields under a constant current. In addition, the reaction was easy to scale up and maintained a good yield. Preliminary mechanism studies suggested that the reaction undergoes a free-radical addition and hydrogen elimination pathway.