The asymmetric epoxidation of vitamin K3 and analogues in aqueous alkaline buffer solution or in DMF/solid Na2C03, in the presence of a-and 8-cyclodextrin has been investigated. The enantiomeric excesses in the products were up to 48%. The various factors that control the enantioselectivity of the process have been examined. Different mechanisms are involved in aqueous medium and dipolar aprotic solvent.
