Desymmetrization of the anti-meso-Acetylmethyldivinylcyclopentane by ­Directed Epoxidation and its Application to the Synthesis of a ­Polyfunctionalized trans-Hydrindane Unit

Desymmetrization of the anti-meso-acetylmethyldivinyl cyclopentane was realized through a three-step sequence involving reduction of the ketone moiety, bishomoallylic alcohol-directed epoxidation and Dess-Martin oxidation leading to the epoxy ketone as a single diastereoisomer. The epoxy ketone was efficiently converted to a trans-hydrindane unit, which constitutes an excellent precursor for the preparation of steroids and their seco-B analogues such as vitamin D3 and its metabolites.