Photocatalytic oxygenation of olefins with oxygen: Isolation of 1,2-dioxetane and the photocatalytic O–O bond cleavage

Formation of 1,2-dioxetane of tetraphenylethylene (TPE) occurs via formation of the electron transfer state of 9-mesityl-10-methylacridinium ion (Acr+-Mes) under visible light irradiation, followed by electron transfer from TPE to the Mes+ moiety together with electron transfer from the Acr moiety to O2, and the subsequent radical coupling between TPE+ and O2− to yield the corresponding 1,2-dioxetane. The dioxetane thus formed was isolated using column chromatography. Photooxygenation of stilbene derivatives is also efficiently catalyzed by Acr+-Mes, accompanied by efficient cis–trans isomerization, to afford the corresponding benzaldehydes via electron transfer from Acr-Mes+ to stilbene derivatives and oxygen.