The total synthesis of (-)-aromadendrene from commercially available (-)-3S-citronellol is presented. (-)-Aromadendrene is a naturally occuring tricyclic sesquiterpene containing a hydroazulene ring. Construction of the requisite hydroazulene nucleus will be achieved in novel fashion via an intramolecular [3+4] allyl cation cycloaddition. Determination of this reaction's diastereoselectivity will be undertaken and has significance to the utility of this general approach to hydroazulene nuclei. This research has relevance to the chemistry of pseudoguaianolides, a large class of structurally related tricyclic sesquiterpenes, many of which exhibit cytotoxic and antineoplastic activities. If successful, this investigation will provide a new entry to the hydroazulene ring system and demonstrate methodology which is readily adaptable to the syntheses of several members of the pseudoguaianolide family, e.g., dasmin, hysterin, ambrosin and helenalin.
