Synergistic action of ozone and O -nucleophiles induces unexpected ring expansion of cycloalkenes into medium-sized peroxycycles.

Visible-light photocatalysis enables the integration of classical electrophile/nucleophile chemistry with radical species (free radicals, radical cations, and radical anions) and metallocomplexes, significantly expanding the scope of organic transformations. Substrates capable of generating radicals via single-electron transfer (SET) are therefore of high value in this field. Among conventional radical precursors, organic peroxides occupy a distinctive position due to their unique reactivity. They can generate both oxygen-centered and carbon-centered radicals through either oxidative or reductive SET pathways. Furthermore, organic peroxides can act as radical precursors, nucleophiles, and oxidants. The review emphasizes the advancements of visible-light-mediated reactions utilizing the broad potential of organic peroxides for constructing various chemical bonds.

A tunable and selective acid-catalyzed method is presented for converting 1,4-diketones into a range of structurally distinct cyclic organic peroxides, including ozonides, tetraoxanes, dihydroperoxy-1,2-dioxanes and dihydroperoxyfurans.