Unified Total Synthesis, Stereostructural Elucidation, and Biological Evaluation of Sarcophytonolides.

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 SmI-mediated fragment coupling, alkoxycarbonylallylation, macrolactonization, and transannular ring-closing metathesis.

Total synthesis of two possible diastereomers of (+)-sarcophytonolide C and its structural elucidation.

Stereoselective and parallel total syntheses of two possible diastereomers of (+)-sarcophytonolide C have been accomplished. Macrolactonization and transannular ring-closing metathesis (RCM) were the key transformations. Detailed comparisons of their (1)H and (13)C NMR data and specific rotation with those of the natural product allowed the absolute configuration of (+)-sarcophytonolide C to be determined.