Aerobic oxidative synthesis of 2-arylbenzimidazoles, 2-arylbenzoxazoles, and 2-arylbenzothiazoles from arylmethanols or arylmethylamines catalyzed by Fe(III)/TEMPO under solvent-free conditions

A simple and efficient aerobic oxidative synthesis of 2-arylbenzimidazoles, 2-arylbenzoxazoles, and 2-arylbenzothiazoles from arylmethanols or arylmethylamines with o-phenylenediamine, o-aminophenol and o-aminothiophenol catalyzed by Fe2(SO4)3/TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl) system under solvent-free conditions. This reaction uses air as an environmental and economic oxidant, tolerates a variety of functional groups on the aromatic ring of the benzylic partner, and affords the products in moderate yields.