ON THE FORMATION AND REACTIVITY OF DIOXIRANE INTERMEDIATES IN THE REACTION OF PEROXOANIONS WITH ORGANIC SUBSTRATES*

Abstract— Kinetics and ¹⁸O-labeling studies have provided evidence for the involvement of dioxirane intermediates (V) in the ketone-catalysed decomposition of peroxomonosulfate (Caroate) HSO;. Reaction rates depend on ketone structure. In competition with catalysis of peroxide decomposition, the dioxirane intermediate is capable of oxidizing several organic and inorganic substrates. Thus, cis- and rrans-cinnammic acids could be converted stereospecifically into the corresponding epoxides. Also, oxidation of phenylpropiolic acid, a substrate which is representative of weakly nucleophilic alkynes, could be carried out using the Caroatehetone oxidizing system. Under the conditions adopted, no oxidation of the substrates examined was found to occur in the absence of ketone. The possibility that formation of dioxathiirane intermediates (XXII) occurs following a side pathway in the reaction of Caroate with sulfoxides (which produces sulfones in high yield) has been explored. Preliminary experiments using ¹⁸O-labeling of p-tolyl phenylsulfoxide, however. failed to support this hypothesis. pointing out the need for further detailed studies.