 <unk> of alkenes is a common reaction because epoxides can be <unk> in a number of useful ways . Classically , laboratory epoxidation is carried out with <unk> or other <unk> . <unk> have been found to be useful for the formation of highly acid sensitive epoxides . ( − ) <unk> was synthesized via <unk> epoxidation as a late stage transformation as seen below . 
