Novel iodinated diterpenes from a marine cyanobacterium and red alga assemblage

[GRAPHICS] Tasihalides A and B have been isolated from an assemblage of a marine cyanobacterium, belonging to the genus Symploca, and an unidentified red alga. The gross structures and relative stereochemistries of these diterpenes were elucidated by spectroscopic means. In addition to possessing a novel cage structure, the tasihalides represent the only examples of iodinated diterpenes in nature.