Synthesis of 1,3-Dioxan-2-ones by Photo-Aerobic Selenium-π-Acid Multicatalysis.

An expedient method for the synthesis of cyclic carbonates from homoallylic carbonic acid esters by means of photo-aerobic selenium-π-acid multicatalysis is reported. Until now, conceptually related methods commonly relied either on the stoichiometric addition of electrophiles onto the substrate's alkene moiety or the presence of pre-installed leaving groups in allylic position of said alkene to - in part, catalytically - initiate an intramolecular attack by an adjacent carbonic acid ester group. In sharp contrast, the current study shows that the C-C double bond of homoallylic carbonic acid esters can be directly activated by the catalytic interplay of a pyrylium dye and a diselane using ambient air as the sole oxidant and visible light as an energy source.