Preparation of S-arylsulfoniacyclane salts

Abstract

S-(4-Hydroxyaryl)sulfoniacyclane perchlorates have been obtained by the condensation of thiacyclanes with phenols in the presence of perchloric acid, phosphorus oxychloride, and hydrogen peroxide, or by condensing thiacyclane S-oxides under the same conditions but without the hydrogen peroxide. The capacity for forming sulfonium perchlorates decreases sharply in the sequence tetrahydrothiophene >thiacyclohexane>thiacycloheptane > methylthiacyclohexane; no sulfonium salts are obtained under these conditions from 2,2,6,6-tetramethylthiacyclohexane, 2-methyl-1-thiadecalin, or 2,5-dimethyltetrahydrothiophene. The S-(4-hydroxyaryl)sulfoniacyclane perchlorates take part in double-decomposition reactions, giving picrates, chlorides, and phosphates. The action of caustic potash in methanol on S-(4-hydroxyphenyl)tetrahydrothiophenium salt forms a dimeric sulfobetaine.