Difluoromethylation of Arylsulfonium Salts with TMSCF 2 H

A catalyst-free difluoromethylation of arylphenothiazinium salts with TMSCF₂H in DMF in the presence of CsF is achieved. The reaction proceeded smoothly at room temperature to furnish the corresponding difluoromethylated products in good yield with excellent selectivity through the formation and ligand coupling of sulfurane intermediates. This protocol represents the first catalyst-free difluoromethylation of arylsulfonium salts, exhibiting features distinct from those of previously reported metallophotocatalytic fluoroalkylation.