An enantiospecific approach to (+)-thaps-8(11)-en-3-ol

An enantiospecific synthesis of a thapsane containing an oxygen substituent at the C-3 position is accomplished starting from (R)-carvone. A Claisen rearrangement and an intramolecular diazoketone cyclopropanation reaction were employed for the stereo- and regiospecific generation of the three contiguous quaternary carbon atoms present in the thapsanes.