Photooxygenation of vinyl sulfides: Substituent effects on the [2+2] cycloaddition versus Schenck ene reaction modes

Article abstract of DOI:10.1016/0040-4039(95)01669-9

Electron-accepting substituents at the para position of aryl vinyl sulfides 1 promote the ene reaction with singlet oxygen in competition with the usual [2+2] cycloaddition, while electron-donating substituents afford exclusively dioxetane product, which through their thermally labile nature decompose by C-C cleavage to the corresponding carbonyl fragments.