Scalable Synthesis of the Shelf-Stable Radical Difluoromethylthiolation Reagent S-(Difluoromethyl)benzenesulfonothioate PhSO2SCF2H

A procedure for the convenient preparation of an efficient radical difluoromethylthiolation reagent, namely, S-(difluoromethyl)benzenesulfonothioate (PhSO2SCF2H), was reported. The reagent was synthesized on an approximately 500 g scale in two steps from cheap commodity sodium benzene sulfinate, benzyl mercaptan, and HCF2Cl. The key step of this protocol is to control the amount of chlorine and the reaction temperatures for the generation of key intermediate [HCF2SCl]. Differential scanning calorimetry (DSC) was carried out to demonstrate the stability of PhSO2SCF2H. Furthermore, gram-scale reaction of PhSO2SCF2H with electron-rich aromatic (hetero)hydrocarbons, alkyl carboxylic acids, and olefins was demonstrated.