RESUMEN
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.
RESUMEN
The first enantioselective total synthesis of tricyclic diterpenoid callilongisin B, which was isolated from Callicarpa longissima, has been achieved. The synthetic method includes a diastereoselective 1,4-addition and Hosomi-Sakurai allylation followed by Wacker oxidation, intramolecular aldol reaction to construct a six-membered ring, and oxidative dearomatization accompanied by diastereoselective δ-lactonization.