New mechanistic aspects of anodic monofluorination of halogenoalkyl and alkyl phenyl sulphides

A unique Pummerer type mechanism via fluorosulphonium ions for anodic monofluorination of sulphides is established by comparing the anodic monofluorination of partially halogenated ethyl phenyl sulphides (1, PhSCH2R; R = CF3, CF2H, CFH2, CF2Cl, CClH2) with their anodic methoxylation; simple alkyl phenyl sulphides 2 bearing no electron-withdrawing group could be monofluorinated anodically in satisfactory yields for the first time when tetrahydrofuran was used as a solvent.