Stereochemical Study of Puna'auic Acid, an Allenic Fatty Acid from the Eastern Indo-Pacific Cyanobacterium Pseudanabaena sp.

The isolation and structure elucidation of puna'auic acid, an allenic fatty acid isolated from a marine cyanobacterium, is described. All configurations were first assessed through molecular modeling of NMR and ECD spectra and then confirmed through a straightforward enantioselective total synthesis of puna'auic acid featuring a key reductive opening of a propargylic epoxide.