A Divergent Enantioselective Synthesis of 9-J1-Phytoprostane and 9-A1-Phytoprostane Methyl Ester

The first syntheses of 9-J1-phytoprostane and 9-A1-phytopro- stane methyl ester were achieved enantioselectively using a divergent approach from a common intermediate sulfone 4. The divergence was accomplished using a sigmatropic re- arrangement (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 olefination reactions of sulfones 4 and 5, with the same enantiopure α-protected aldehyde 6.