Treatment of gamma-butyrolactone (I) with N,O-dimethylhydroxylamine in the presence of dimethylaluminium chloride afforded the corresponding Weinreb amide (II), which was converted to the keto-alcohol (III) by addition of pentylmagnesium bromide. Swern oxidation of alcohol (III), followed by Wittig reaction of the resultant aldehyde (IV) with (methoxycarbonylmethylene)triphenylphosphorane (V), provided the unsaturated keto ester (VI). Subsequent scandium triflate-mediated peroxyhemiacetalyzation of ketone (VI) gave rise to (VII). Then, intramolecular Michael addition of the hydroperoxy ester (VII) in the presence of diethylamine generated the target cyclic peroxide.