Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

A Ti-III-mediated radical cyclization cascade has been used for the synthesis of the sesquiterpenes (+)-albicanol, (+)-drimanol, and (+)-drimanic acid. Starting from all-transfarnesol, (+)-albicanol could be prepared in seven steps in an overall yield of 14.9%. Furthermore, a highly diastereoselective hydrogenation of (+)-albicanol to give (+)-drimanol has been developed. We used the synthesized (+)-drimanic acid to achieve the first synthesis of the marine sesquiterpene hydroquinone deoxyspongiaquinol and the quinone deoxy-spongiaquinone. Thus, this synthetic strategy gave access to five natural products.