The first syntheses of 9-J1-phytoprostane and 9-A1-phytoprostanemethylester were achieved enantioselectively using a divergent approach from a common intermediate sulfone 4. The divergence was accomplished using a sigmatropic rearrangement (swap protocol) to give sulfone 5 in 47 % overall yield. The two upper side-chains, with a stereodefined E double bond, were installed using consolidated Julia–Lythgoe