Synthesis of elenic acid, an inhibitor of topoisomerase II

A short, efficient synthesis of elenic acid, a marine natural product with interesting biological activity, has been completed. Critical features of the synthesis are the development of methodology for the one-pot elaboration of an alkyne to an (E)-beta,gamma-unsaturated ester with a stereocenter at the alpha-position and the use of the zipper reaction of a 1-arylalkyne. This reaction has not been previously reported with aromatic substrates. The synthesis strategy provides considerable flexibility for the preparation of structural analogues.