Electrochemical C-H/N-H cross-coupling of 2-phenylindolizines with phenothiazines to synthesize novel N-aryl phenothiazine derivatives

A facile and elegant method for synthesis of novel N-aryl phenothiazine derivatives from 2-phenylindolizines and phenothiazines through direct electrochemical oxidation has been developed.This approach was performed smoothly at room temperature without external oxidant and catalyst.Cyclic voltammetry and in situ FTIR techniques were applied to analyze the cross-coupling process of phenothiazines and 2-phenylindolizines,which helped to select the appropriate reaction potential.Under the optimized conditions,a broad range of substrates were well tolerated,affording the desired products in moderate to excellent isolated yields(up to 91%)with high regioselectivity.Meanwhile,a plausible mechanism involving a radical pathway has been proposed.