The first total synthesis of IPF2 alpha-III, a type III isoprostane is described using a syn-anti-syn lactone 34 prepared from D-glucose and a novel iodohydrin synthon 30. This is first synthesis of a representative of type III isoprostane which is anticipated to be formed in vivo from arachidonic acid by free-radical mechanism. This synthetic material will help elucidate the formation in vivo of type III isoprostanes. (C) 1997 Elsevier Science Ltd.