First Total Synthesis of a Polyunsaturated Chromone Metabolite Isolated from the Brown Algae Zonaria tournefortii

Starting from the ethyl ester of eicosapentaenoic acid, the first total synthesis of the marine natural product all-(Z)-5,7-dihydroxy-2(4Z, 7Z,10Z,13Z,16Z-nonadecapentaenyl)chromone has been achieved in six steps and in 14% overall yield.