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In this work, ZnO2 was unexpectedly discovered as a friendly and renewable source of anhydrous hydrogen peroxide in the acid-catalyzed synthesis of cyclic organic peroxides from carbonyl compounds. In particular, five classes of cyclic organic peroxides, namely, γ-hydroperoxy-γ-peroxylactones, β-hydroperoxy-β-peroxylactones, bridged ozonides, bridged 1,2,4,5-tetraoxanes, tricyclic monoperoxides, and tricyclic diperoxides, were synthesized in good yields using in situ generated H2O2 from the reaction of ZnO2 with H2SO4. This approach is convenient, safe, and does not require a concentrated aqueous or ethereal solution of H2O2. The starting ZnO2 was synthesized from zinc acetate using a 1 wt% H2O2 solution. The reaction of zinc peroxide with sulfuric acid in an organic solvent results in the release of hydrogen peroxide and the formation of zinc sulfate, which acts as a desiccant by forming a monohydrate phase, ZnSO4·H2O. The possibility of recycling zinc peroxide from zinc sulfate monohydrate with a high yield was shown. [ABSTRACT FROM AUTHOR]

Stereoelectronic interactions control reactivity of peroxycarbenium cations, the key intermediates in (per)oxidation chemistry. Computational analysis suggests that alcohol involvement as a third component in the carbonyl/peroxide reactions remained invisible due to the absence of sufficiently deep kinetic traps needed to prevent the escape of mixed alcohol/peroxide products to the more stable bisperoxides. Synthesis of β-alkoxy-β-peroxylactones, a new type of organic peroxides, was accomplished by interrupting a thermodynamically driven peroxidation cascade. The higher energy β-alkoxy-β-peroxylactones do not transform into the more stable bisperoxides due to the stereoelectronically imposed instability of a cyclic peroxycarbenium intermediate as a consequence of amplified inverse alpha-effect. The practical consequence of this fundamental finding is the first three-component cyclization/condensation of β-ketoesters, H 2 O 2 , and alcohols that provides β-alkoxy-β-peroxylactones in 15-80 % yields., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)