Absolute configuration of cembrane diterpenoids from Bursera multijuga.

The stems of Bursera multijuga afforded (-)-(1S,3E,7R,8R,11E)-7,8-epoxycembra-3,11-dien-1-ol (1) and its acetate 2, together with cembrene A (3), nephthenol (4), and cembrenol (5). The structures o...