Synthesis of unsymmetrical bisperoxides via semicarbazone ozonolysis in the presence of hydroperoxides

Abstract

A selective method has been developed for the synthesis of unsymmetrical geminal bisperoxides via the ozonolysis of semicarbazones in a hydroperoxide containing medium. The replacement of the CN moiety by two different peroxide fragments bonded to the same carbon atom in a one-pot process is a step towards solving the complex problem of organic synthesis: geminal difunctionalization with two closely related, but not identical, functional groups. Our approach is based on the relatively unexplored ozonolysis of the CN fragment. The probable reaction pathway involves the cycloaddition of the ozone molecule to the CN fragment, followed by the formation of carbonyl oxide, which then undergoes nucleophilic trapping with hydroperoxide to form an unsymmetrical bisperoxide. The synthesis of unsymmetrical bisperoxides has been accomplished using the following hydroperoxides as nucleophiles: tert-butyl hydroperoxide, cumyl hydroperoxide and tetrahydropyran-2-yl hydroperoxide. This disclosure provides access to a range of difficult-to-reach unsymmetrical bisperoxides with yields up to 62%.