合成路线1

Reformatskii condensation of the organozinc reagent derived from methyl bromoacetate (XIII) with n-heptyl cyanide (XII) gave rise to the keto ester adduct (XIV). Catalytic hydrogenation of (XIV) in the presence of the chiral catalyst generated from dichloro(cycloocta-1,5-diene)ruthenium and (R)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl furnished the (R)-hydroxyester (XV) in high enantiomeric excess. Ester group reduction in (XV) by means of LiAlH4 afforded diol (XVI), which was further converted to the primary tosylate (XVII) with p-toluenesulfonyl chloride in pyridine. Then, alkylation of the intermediate alcohol (XI) with tosylate (XVII) under Williamson's ether synthesis conditions provided the common precursor (XVIII).