Marine antitumor agents: 14-deoxycrassin and pseudoplexaurol, new cembranoid diterpenes from the Caribbean gorgonian Pseudoplexaura porosa.

Two new cytotoxic antitumor diterpenoids of the cembrane class, named 14-deoxycrassin (3) and pseudoplexaurol (4), have been isolated from the Caribbean gorgonian octocoral Pseudoplexaura porosa. The structure of lactone 3, possessing the infrequently encountered alpha-methylene-delta-lactone ring, has been established from spectral and chemical data and that of alcohol 4 has been established from spectral data.