of the Corey lactone, has been prepared from a readily available nortricyclanone derivative by a five-step sequence in an overall yield of 34 %. This chiral buildingblock has been applied in total syntheses of two diastereomeric isoprostanes belonging to the 5-F2 family: ent-5-F2c-IsoP (ent-1) and 5-epi-ent-5-F2c-IsoP (ent-2). Key features of the syntheses are the introduction of the two unsaturated