Relative and Absolute Stereochemistry of the Didemnaketals, Metabolites of a Palauan Ascidian, Didemnum sp.

The absolute stereochemistry of the heptaprenoids didemnaketals B (2) and C (3), isolated from a Palauan ascidian, was determined using a combination of degradation and derivatization experiments, chiral shift methods, and comparison of fragments to known compounds.