Study on the oxidation reaction of organic compounds with peroxysulfur intermediate

Abstract

A new peroxy species of 2-nitrobenzene peroxysulfur intermediate generated from 2-nitrobenzene peroxysulfur intermediate generated from 2-nitrobenzenesulfonyl chloride and potassium superoxide is proven to be an excellent oxidizing agent for the various organic compounds. These include regioselective epoxidation of olefins, direct oxidation of arenes to arene oxides, oxidative cleavage of tosylhydrazones to their carbonyl compounds, facile oxidation of sulfides and sulfoxides to their sulfoxides and sulfones respectively, and oxidation of substrates having benzylic methylene group to the corresponding carbonyl compounds. These oxidation reactions seem to be proceeded via electrophilic radical mechanism resulting from the following evidences: (a) nonstereoselective epoxidation of cis-stilbene to the trans-epoxide and cis-epoxide (transepoxide: cis-epoxide = 3:1) and trans-epoxidation of trans-stilbene. (b) competitive oxidation between sulfide and sulfoxide showed that sulfides were more rapidly oxidized to sulfoxides than sulfoxides to sulfones ca. 9-19 times. (c) comparison of Hammett``s $\rho$ values for the epoxidation of styrenes: -1.56, for the oxidation of sulfides to the sulfoxides: -1.54, for the oxidation of sulfoxides to the sulfones: -1.39, and for the oxidation of methylene group of toluenes: -1.15 were observed. (d) epoxidation of olefin and oxidation of sulfide and sulfoxide to sulfoxide and sulfone respectively were inhibited significantly by addition of DABCO. o-Nitro group of 2-nitrobenzene peroxysulfur intermediate seems to play an important role for stabilizing the electron dificient sulfur center with the oxygen end of o-nitro goup of 2-nitrobenzene peroxysulfur intermediate. 2-Nitrobenzene peroxysulfur intermediate, which is a new peroxy radical species as an excellent oxidizing agent for the oxidation of various organic compounds via a strong electrophilic radical mechanism, seems to be significant not only in organic synthesis but also in...