Transition metal-free synthesis of polyfluoroaryl sulfides via S-transfer reaction

We report herein an efficient, transition metal-free protocol for synthesizing polyfluoroaryl sulfides using cheap and odorless sulfur reagents, specifically thiourea and potassium thioacetate. A key advancement in this method is the identification of thioamides as effective S-transfer reagents, which react with polyfluoroarenes to form symmetrical polyfluorodiaryl sulfides. Following extensive optimization, the protocol demonstrates significant robustness, flexibility, and compatibility with a broad array of functional groups. Additionally, commercially available alkyl bromides and arynes can serve as secondary electrophiles, coupling with polyfluoroarene-substituted sulfur anion intermediates to produce unsymmetrical polyfluoroaryl sulfides. The practicality of the method is further investigated by its facile gram-scale synthesis, diverse synthetic applications, and potential for late-stage functionalization, highlighting its utility in advancing aryl sulfide and fluorine chemistry. Mechanistic insights were elucidated through crossover, control, and radical inhibition experiments.