Efficient Epoxidation of alkenes with aqueous hydrogen peroxide catalyzed by methyltrioxorhenium and 3-cyanopyridine

The epoxidation of alkenes with 30% aqueous hydrogen peroxide:is catalyzed efficiently by methyltrioxorhenium (MTO) in the presence of pyridine additi ves. The addition of 1-10 mol % of 3-cyanopyridine increases the system's e fficiency for terminal and trans-disubstituted alkenes resulting in high is olated yields of the corresponding epoxides. The system allows for epoxidat ion of alkenes with Various functional groups. Alkenes leading to acid-sens itive products are efficiently epoxidized using a mixture of pyridine and 3 -cyanopyridine as additives. This method is operationally very simple and u ses an environmentally benign oxidant.,The effects of different pyridine ad ditives on the alkene conversion and the catalyst lifetime are discussed.