Scopariusins, a new class of ent-halimane diterpenoids isolated from Isodon scoparius, and biomimetic synthesis of scopariusin A and isoscoparin N.

Scopariusins A-C (1-3), three novel rearranged ent-halimanoids with a bicycle[5.4.0]undecane ring system, two new normal ent-halimanoids (4 and 5), and a new ent-clerodanoid (6) were isolated from Isodon scoparius. Moreover, a biomimetic transformation from the ent-clerodanoid to the normal and the rearranged ent-halimane diterpenoids was successfully accomplished, which not only validated the biogenetic hypothesis in this plant but also confirmed the absolute configurations of 1 and 5.