Oxidative cleavage of α-substituted styrenes using excited dibenzothiophene S-oxide and DMSO

Visible-light-induced oxidative cleavage of α-substituted styrenes has been achieved using a photocatalyst, dibenzothiophene S-oxide, and DMSO. The reaction proceeds via an addition of a methyl radical to the styrenic double bond, representing a mechanistically distinct pathway compared with conventional methods for oxidative cleavage that rely on toxic and/or explosive oxidants. This unique radical mechanism enables interesting chemoselectivities such as preferential oxidation of electron-deficient alkenes over electron-rich ones as well as provides an environmentally benign alternative for oxidative cleavage.