合成路线1

The esterification of 4alpha-carboxymethyl-5beta-benzyloxymethyl-cyclopent-2-en-1alpha-ol (I) with methyl iodide and K2CO3 in acetone gives the corresponding methyl ester (II), which by reaction with triethyl - orthoacetate (III) at 145 C is converted into 3-ethoxycarbonylmethyl-4-methoxycarbonylmethyl-5-benzyloxymethyl-1-cyclopentene (IV). The cyclization of (IV) with potassium tert-butoxide in benzene yields 6-benzyloxymethyl-cis-bicyclo[3.3.0]oct-7-ene-3-one (V), which by reaction with N-bromosuccinimide in DMSO - water affords 6-benzyloxymethyl-7-hydroxy-8-bromo-cis-bicyclo[3.3.0]octan-3-one (VI). Debromination of (VI) with tributyltin hydride and azobisisobutyronitrile in benzene irradiated with UV light gives 6-benzyloxymethyl-7-hydroxy-cis-bicyclo[3.3.0]octan-3-one (VII), which is treated with dihydropyran and p-toluenesulfonic acid in methylene chloride yielding the corresponding protected compound (VIII). Elimination of the benzyl group of (VIII) with H2 over Pd/C in acetic acid affords 6-hydroxymethyl-7-(tetrahydropyranyloxy)-cis-bicyclo[3.3.0]octan-3-one (IX), which is submitted to a Wittig condensation with (4-carboxybutyl) triphenylphosphonium bromide (X) and the sodium salt of DMSO in this solvent, followed by a methylation with diazomethane, affording 3-(4-methoxycarbonylbutylidene)-6-hydroxymethyl-7-tetrahydropyranyloxy)-cis-bicyclo[3.3.0]octane (XI). Oxidation of (XI) with CrO3 in methylene chloride gives the corresponding 6-formyl derivative (XII), which is submitted to a new Wittig condensation with dimethyl 2-oxo-2-cyclopentylethylphosphonate (XIII) and NaH in THF yielding methyl 6,9-methano-11-(tetrahydropyranyloxy)-15-oxo-15-cyclopentyl-16,17,18,19,20-pentanorprosta-3,5-dienoate (XIV). Deprotection of (XIV) with acetic acid in THF - water gives the corresponding 11-hydroxy compound (XVI), which is reduced with NaBH4 in methanol affording the 11,15-dihydroxy ester (XVI). Finally, this compound is hydrolyzed with NaOH in methanol - water.