摘要:
Asymmetrized 2-alkenyl 1,3-propanediols are stereoselectively epoxidized to the same main diastereoisomer both with 3-chloroperbenzoic acid and the VO(acac)2/t-butyl hydroperoxyde system. Using the latter epoxidating reagent in combination with a protection-deprotection sequence involving the two homoallylic hydroxy groups, all the four cis epoxides were easily achieved in stereoisomeric pure form starting from a single common (Z) precursor.