合成路线1

Desilylation of commercial Corey's lactone (I) with TBAF in THF gives carbinol (II), which is oxidized by means of (COCl)2 and DMSO in dichloromethane to yield the carbaldehyde (III). Condensation of compound (III) with phosphonate (IV) by means of thallium ethoxide in dichloromethane affords the unsaturated difluoroketone (V), which is reduced with H2 over Pd/C in ethyl acetate to afford the saturated ketone (VI). Reduction of ketone (VI) with NaBH4 in methanol provides the secondary alcohol (VII), which is further reduced with diisobutylaluminum hydride in toluene to give the lactol (VIII). Condensation of lactol (VIII) with 4-carboxybutyl triphenylphosphonium bromide (IX) by means of t-BuOK in THF yields the prostaglandin F2a derivative (X), which is esterified by means of benzyl bromide and DBU in dichloromethane to afford the benzyl ester (XI). Oxidation of ester (XI) with CrO3 and pyridine in dichloromethane provides the THP-protected prostaglandin E2 derivative (XII), which is treated with AcOH in THF/water to give the prostaglandin E2 benzyl ester derivative (XIII). Finally, this compound is submitted to simultaneous benzyl ester group cleavage and double bond reduction by means of H2 over Pd/C in ethyl acetate.