Sulfinium cation

A sulfinium cation (80) was suggested as a probable intermediate in the ring closure of sulfinyl chlorides by Lewis acids in an intramolecular ene reaction (Kukolja, 1977). The process is visualized as a complexation of the Lewis acid with either the oxygen or the chlorine atom of the sulfinyl chloride followed by formation of the S—C-2 bond with olefinic carbon, concomitant with hydrogen abstraction from the methyl group of the isopropenyl functionality (Scheme 4). In support of this mecha-... 

An analogous reaction is observed in the dimerization of phenylsulfides in which sulfonium salt products are formed presumably through the intermediacy of a sulfinium cation-radicalPappas and his coworkers have determined an apparent second order rate constant of 8 x 10 liter/mol. sec. for the reaction of the phenyliodinium cation-radical with iodobenzene, indicating that this is an extraordinarily facile process. Here again, further reaction of the iodobenzene radical by, for example, coupling, could deplete iodobenzene relative to that acid which is formed. 

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