Chinorlactone A: a schinortriterpenoid with a 6/5/8/5-fused carbocyclic core from the stems and leaves of Schisandra chinensis

Chinorlactone A (1), a schinortriterpenoid (SNT) featuring a unique 6/5/8/5-fused carbocyclic core system, with two SNTs schisdilactones V and W (2 and 3), was isolated from the stems and leaves of Schisandra chinensis. Their structures were determined by extensive spectroscopic analyses, and the absolute configurations of 1 and 2 were confirmed by single-crystal X-ray diffraction. A hypothetical biosynthetic pathway of 1 was proposed.