合成路线1

The Wittig condensation of cis-bicyclo[4.3.0]nona-3-en-8-one (I) with triethyl phosphonoacetate (II) by means of NaH in THF gives 2-(cis-bicyclo[4.3.0]octa-3-en-8-ylidene)acetic acid ethyl ester (III), which is reduced with Li in liquid ammonia to the corresponding ethanol derivative (IV). The condensation of (IV) with N-benzyl-2-chloro-N-phenylacetamide (V) by means of NaH in toluene affords the corresponding ethoxyacetamide (VI), which is treated with ozone in methanol to give the epoxide (VII). Cleavage of (VII) with dimethyl sulfide in the same solvent yields the dialdehyde (VIII), which is submitted to an aldol cyclization by means of NaOH in methanol/water to afford the 2beta-formyl-3alpha-hydroxy derivative (IX). The Wittig condensation of aldehyde (IX) with dimethyl 4(S)-methyl-2-oxooctylphosphonate (X) by means of NaH in THF gives the unsaturated hydroxy ketone (XI). The ketone group of (XI) is reduced with NaBH4 in methanol, and the resulting diastereomeric diols obtained are separated by column chromatography to yield the alpha,alpha-dihydroxy compound (XII). The hydrolysis of (XII) with KOH in refluxing ethanol/water yields the corresponding free acid (XIII), which is finally methylated with diazomethane in ethyl ether to obtain a mixture of the epoxy alcohol (XXIVa) and the unsaturated alcohol (XXIVb). A chromatographic separation of the mixture followed by desilylation with acetic acid in methanol gives the desired final product.