合成路线1

The reaction of 5-norbornen-2,3-dicarboxylic anhydride (XXXVII) with hot H2SO4 gives the lactone (XXXVIII), which is reduced with diborane in THF yielding the hydroxylactone (XXXIX). The mesylation of (XXXIX) as usual gives the ester (XL), which by reaction with NaCN in DMSO is converted into the cyanolactone (XLI). The reduction of the lactone ring with LiBH4 in diglyme affords the dihydroxynitrile (XLII), which by benzoylation and oxidation with Jones reagent yields the benzoylated cyanoketone (XLIII). The oxidation of (XLIII) with peracetic acid gives the benzoylated cyanolactone (XLIV), which by methanolysis with H2SO4 and methanol is converted into the cyanoester (XLV). The protection of the free alcohol of (XLV) with dihydropyran and debenzoylation of the resulting product affords the hydroxymethyl cyanoester (XLVI), which by oxidation with pyridinium chlorochromate is converted into the aldehyde (XLVII). The Wittig reaction of (XLVII) with the phosphonate (IX) yields the ketonic cyanoester (XLVIII), which is reduced with NaBH4 to the corresponding alcohol (XLIX). The reaction of (II) with dihydropyran affords the corresponding bis(tetrahydropyranyl) derivative (L).