Asymmetric Total Synthesis of Propindilactone G

A concise total synthesis of (+)-propin­di­lactone G, a nor­tri­terpenoid isolated from the stems of <i>Schisandra propinqua</i> var. <i>propinqua</i>, has been achieved for the first time. The key steps of the synthesis include an asymmetric Diels–Alder reaction, a Pauson–Khand reaction, a Pd-catalyzed reductive hydrogen­olysis reaction, and an oxidative hetero­coupling reaction. These reactions enabled the synthesis of (+)-propin­di­lactone G in only 20 steps. As a consequence of our synthetic studies, the structure of (+)-propin­di­lactone G has been revised.