Direct, Metal-free C(sp2 )-H Chalcogenation of Indoles and Imidazopyridines with Dichalcogenides Catalysed by KIO3

Abstract

Herein, we report a greener protocol for the synthesis of 3-Se/S-indoles and imidazo[1,2-a]pyridines through direct C(sp² )-H bond chalcogenation of heteroarenes with half molar equivalents of different dichalcogenides, using KIO₃ as a non-toxic, easy-to-handle catalyst and a stoichiometric amount of glycerol. The reaction features are high yields, based on atom economy, easy performance on gram-scale, metal- and solvent-free conditions as well as applicability to different types of N-heteroarenes.

Keywords: KIO3; cross-coupling; green chemistry; nitrogen heterocycles; selenium.