A green route to epoxides: Catalytic selective epoxidation of alkenes with 1 atm molecular oxygen with 10000 turnover number

The Keggin-type diiron-substituted silicotungstate has been used as catalysts for the oxygenation of alkenes in homogeneous reaction media using molecular oxygen as an oxygen donor. It is remarkable that selectivity to cyclooctene oxide and turnover number reached up to 98% and 10000, respectively, for the oxygenation of cyclooctene. Not only cyclooctene but also cyclododecene, 1-octene, 2-octene, 2-heptene and 2-hexene were catalytically oxygenated with high turnover numbers and high selectivity to the corresponding epoxides. It was also suggested that diiron-substituted polyoxometalate was stable under the conditions used.