Studies towards the synthesis of polyoxygenated steroids. Reaction of some tri- and tetrasubstituted monoene steroids with ruthenium tetroxide

The course of the reaction of ruthenium tetroxide with some tri- and tetra-substituted nuclear monoene steroids, namely δ4, δ5, δ7 and δ8(14)-steroids, has been investigated in acetone-water or carbon tetrachloride as solvent systems using stoichiometric amounts of the oxidant. In contrast with results previously reported for RuO4 oxidations, we found that trisubstituted double bonds gave α-hydroxy ketones and/or 1,2-diols rather than the expected products deriving from the scission of the carbon-carbon double bond. Scission of the double bond indeed occurs when fully substituted steroidal alkenes are oxidized. Only in the case of the δ8(14)-steroid, an allylic oxidation product wa obtained in addition to the scission product. The change in the solvent system seems to profoundly affect the course of the reaction.