Enantiospecific total syntheses of (-)-valeranone

Two convenient methodologies are described for the enantiospecific synthesis of (-)-valeranone. The hydrindanone I, obtained from the readily and abundantly available monoterpene (R)-carvone, was converted into the ketoaldehyde II via an alkene. In another direction the lactone III, obtained from the hydrindanone I, has been elaborated into the ketoaldehyde II employing two methodologies. Intramol. aldol condensation followed by hydrogenation transformed the ketoaldehyde II into (-)-valeranone