Original syntheses of epoxides involving organoselenium intermediates

β-oxidoalkylselenonium salts and β-oxidoalkylselenones are valuable precursors of a large variety of epoxides. These species were synthesized by reaction of α-selenonio or α-selenonylalkylpotassium with carbonyl compounds or by reaction of a suitable base on β-hydroxyalkylselenonium salts or β-hydroxyalkylselenones, themselves obtained from β-hydroxyselenides. The most powerful method, based on the cyclization of β-hydroxyalkylselenonium salts is fully documented.