Metal-free (Boc)2O-mediated C4-selective direct indolation of pyridines using TEMPO

Abstract

Direct metal-free C-4-selective indolation of pyridines is achieved for the first time using TEMPO and (Boc)₂O. A variety of substituents on both indoles and pyridines are tolerated to give 3-(pyridin-4-yl)-1H-indole derivatives in moderate to excellent yields. This finding provides a novel approach for developing metal-free C–H functionalization of pyridines.