Elisapterosins D and E: complex polycyclic diterpenes of the rare elisapterane class of natural products from the Caribbean sea whip Pseudopterogorgia elisabethae (Bayer)

From the hexane extracts of a Colombian specimen of Pseudopterogorgia elisabethae (Bayer) we have isolated elisapterosin D (2) and elisapterosin E (3), two structurally complex polycyclic diterpenes based on the rare elisapterane carbon skeleton. The structures of these scanty compounds were elucidated after interpretation of their combined spectroscopic data and NMR spectral comparisons with known elisapterane models.