Asymmetric Total Synthesis of Propindilactone G

A concise total synthesis of (+)-propin­di­lactone
G,
a nor­tri­terpenoid isolated from the stems of Schisandra
propinqua var. propinqua, 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.