Synthesis of methyl (5Z,9Z,17R)-17-methyinonadeca-5,9-dienoate, the (R)-enantiomer of the structure proposed for a metabolite of the Philippine sponge Plakinastrella sp.

The (R)-enantiomer (1) of methyl (5Z,9Z)-17-methyl-nonadeca-5,9-dienoate, the structure proposed for a metabolite of the Philippine sponge, Plakinastrella sp., was synthesized. The H-1- and C-13-NMR spectra of the synthetic material were different from those reported for the natural product. The proposed structure 1 is therefore incorrect.