Photooxygenation of 1,2-Diarylcyclopropanes: Formation of 3,5-Diaryl-1,2-Dioxolanes via Photoinduced Electron Transfer

The photooxygenation of electron-rich 1,2-diarylcyclopropanes such as 1,2-bis(4-methoxyphenyl)cyclopropane and 1-(4-methoxyphenyl)-2-phenylcyclopropane in the presence of 9,10-dicyanoanthracene(DCA) as a sensitizer in acetonitrile affords trans- and cis-3,5-diaryl-1,2-dioxolanes in high yields. This photooxygenation is initiated by the electron transfer from 1,2-diarylcyclopropanes to the excited singlet DCA, involving the cation radical of cyclopropanes as a key intermediate.