Selenium catalysed oxidations with aqueous hydrogen peroxide. Part I: epoxidation reactions in homogeneous solution

Several diselenides were synthesised and tested for catalytic activity in epoxidation reactions with aqueous hydrogen peroxide. Bis[3,5-bis(trifluoromethyl)phenyl] diselenide forms the corresponding 3,5-bis(trifluoromethyl)benzene seleninic acid (L. Syper and J. Mlochowski, Tetrahedron, 1987, 43, 207.) in situ, which is a highly reactive and selective catalyst for the epoxidation of olefins in 2,2,2-trifluoroethanol. This is the first selenium compound that effectively (substrate to catalyst molar ratio s/c=200) catalyses the formation of sensitive epoxides in nearly quantitative yields.