Epoxidation of olefins by ketone-H2O2 system

Epoxidation of olefins was carried with an excellent yield by dioxiranes ge nerated in situ by reaction of ketone with H2O2 in the presence of NaHCO3 i n mixed solvent of acetonitrile and water. The catalytic activity of variou s ketones on epoxidation was studied for the first time. It is found that t he ketone with electron-withdrawing group has an excellent catalytic activi ty and trifluromethyl ketone has the highest catalytic activity. Some bulky ketones with electron-withdrawing group show a very low catalytic activity . For olefins, the electron-withdrawing group decreased the reactivity of t he olefin and the electron-donating group increased the reactivity, but the steric factor has little effect on the reactivity of olefins.