Asymmetric Total Synthesis of (+)-Lemnardosinane A.

The asymmetric total synthesis of (+)-lemnardosinane A, a rare rearranged sesquiterpenoid, has been accomplished from ( S )-carvone. Key features of the synthesis are the formation of a bicyclo[3.3.1]nonane skeleton using the intramolecular aldol reaction, the stereoselective introduction of an alkyne group, and the stereoselective formation of a tricyclic skeleton via intramolecular pinacol coupling.