Transition-metal- and phosphorus-free electrophilic trifluoromethylthiolation of indoles with sodium trifluoromethanesulfinates in ionic liquids

Abstract An acid-promoted protocol has been developed to achieve the transition-metal- and phosphorus-free electrophilic trifluoromethylthiolation of indoles using sodium trifluoromethanesulfinates in an imidazolium-based ionic liquid ([Hmim]Br). [Hmim]Br not only acts as a recyclable solvent, but also as the reductant in this transformation. The advantages of this chemistry include simple operation, use of a recyclable solvent, avoidance of transition-metal and phosphorus, and gram-scale synthesis.