Kinetics and mechanism of the oxidation of organic sulfides

The oxidation of organic sulfides by [bis(trifluoroacetoxy)iodo]benzene (TFAIB), to the corresponding sulfoxides, is first order with respect to TFAIB, hydrogen-ions, and the sulfide. The correlation analyses of the rate of the oxidation of thirty-five sulfides were performed in terms of various single and multiparametric equations. For the aryl methyl sulfides, the best correlation is obtained with Charton's LDR and LDRS equations. The oxidation of alkyl phenyl sulfides exhibited a very good correlation in terms of the Pavelich-Taft equation. The polar regression coefficients are negative. A mechanism involving formation of a sufonium-cation intermediate in the slow step has been proposed.