New synthetic routes to 2alpha,3beta-dihydroxy-5alpha-cholestane

Better synthetic approaches to 2alpha,3beta-dihydroxy-5alpha-cholestane and its ester derivatives, which were hitherto difficult to prepare, are reported. A satisfactory preparation of the desired trans-diequatorial 2alpha,3beta-dibenzoate, starting from the easily available corresponding cis 2alpha,3alpha-diol, has been devised. Finally, the influence of the temperature as well as of the bulkiness of the silver carboxylate on the steric course of the Prevost reaction have also been examined.