Photochemical epoxidation of alkenes by visible light in a redox system involving tetraphenylporphyrinantimony(V) and water

Irradiation with visible light of a mixture of an alkene in degassed aqueous acetonitrile containing tetraphenylporphyrinantimony(V) as a sensitizer, methylviologen as an electron acceptor, and hydroxide ion, induced epoxidation of the alkene accompanied by hydrogen evolution, with water acting as the electron donor.