Excavatoids O and P, new 12-hydroxybriaranes from the octocoral Briareum excavatum.

Two new 12-hydroxybriarane diterpenoids, designated as excavatoids O (1) and P (2), were isolated from the octocoral Briareum excavatum. The structures of briaranes 1 and 2 were established on the basis of extensive spectral data analysis. Excavatoid P (2) is the first metabolite which possesses a 6ß -chlorine atom in briarane analogues.