An indirect method for the oxidation of aryl phosphites to phosphates and aryl selenoxides to selenones

Aryl phosphites and aryl selenoxides are unreactive towards singlet oxygen. However, in the dye-sensitized co-photooxygenation of 1 equivalent of an aryl phosphite or an aryl selenoxide with 1.2-1.5 equivalents of dimethyl sulfide, the corresponding aryl phosphates and aryl selenones are produced with > 90% isolated yield ( 10 examples). The reaction is applicable to phosphites and selenoxides with either electron-donating or electron-withdrawing substituents on the aryl ring.