Synthesis of cyclic peroxides from methyl oleate

Abstract

A mixture of [10(8)E]-9(10)-hydroperoxyoctadec-10(8)-enoates (3a) and (3b), produced by the photosensitised oxidation of methyl oleate, is a suitable substrate for the synthesis of substituted dioxolanes. Peroxymercuriation of (3) followed by hydrogenodemercuriation affords 3-(6-methoxy-carbonylhexyl)-5-octyl- and 5-heptyl-3-(7-methoxycarbonylheptyl)-1,2-dioxolanes (5a) and (5b) in good yield (45–70%). Peroxymercuriation followed by bromodemercuriation yields the corresponding bromo substituted cyclic peroxides (epidioxides)(9a) and (9b) in higher yield (95%). Direct bromination of the allylic hydroperoxides (3a) and (3b) affords the same bromo substituted cyclic peroxides (9a) and (9b) in almost quantitative yield, presumably via a bromonium ion intermediate.