Sarcophytonolides are cembranolide
diterpenes isolated from the
soft corals of genus Sarcophyton. Unified total synthesis
of sarcophytonolides C, E, F, G, H, and J and isosarcophytonolide
D was achieved. The synthetic routes feature NaHMDS- or SmI2-mediated fragment coupling, alkoxycarbonylallylation, macrolactonization,
and transannular ring-closing metathesis. These total syntheses led
to the absolute configurational confirmation of sarcophytonolide H,
elucidation of sarcophytonolides C, E, F, and G, and revision of sarcophytonolide
J and isosarcophytonolide D. We also evaluated the antifouling activity
and toxicity of the synthetic sarcophytonolides H and J and their
analogues as well as the cytotoxicity of the synthetic sarcophytonolides
and the key synthetic intermediates.