Transformations of polyfluoroarenesulfonyl halides with alkenes, polyfluoroarenethiols and alkali metal halides

Polyfluoroarenesulfonyl halides can be successfully used for the introduction of polyfluoroarenesulfonyl moiety in organic compounds. Recently we realized a simple and efficient method for preparation of polyfluoroarenesulfonyl bromides by the action of electrophilic brominating agents on polyfluoroarenethiols. We have shown that the nature of halogen atom in SO₂Hal group influence the chemical properties of polyfluoroarenesulfonyl halides. Thus, the reactions of polyfluoroarenesulfonyl bromides with alkenes such as hexene-1 or allyl chloride provided the corresponding adducts in high yields, while the conversion of polyfluoroarenesulfonyl chlorides at the same conditions was poor and C₆F₅SO₂F was unreactive. The formation of adducts apparently occurs with participation of polyfluoroarenesulfonyl radicals. At the same time the reaction of polyfluoroarenesulfonyl bromides with allyl bromide resulted in allyl polyfluoroaryl sulfones. This fact is explained by the addition of polyfluoroarenesulfonyl radical to alkene double bond and subsequent elimination of bromine. In reactions of allyl polyfluoroaryl sulfones with polyfluoroarenesulfonyl bromides the replacement of Ar_FSO₂ group in sulfone by another one takes place. According to these data the reversibility of allyl polyfluoroaryl sulfone formation can be suggested. Surprisingly the reactions of polyfluoroarenesulfonyl chlorides or bromides with polyfluoroarenethiols gave mixtures of polyfluorinated diaryl disulfides, whereas replacement of fluorine atom at the 4-position of aromatic ring of C₆F₅SO₂F occured. It turned out that reactions of polyfluoroarenesulfonyl chlorides or bromides with some n‑nucleophiles probably proceeded with electron transfer. For example, such process could take place in reactions of polyfluoroarenesulfonyl chlorides or bromides with alkali metal halides.