合成路线1

The selective protection of the primary OH group of hydroxymethyl tetrahydropyran-3-ol (X) with trityl chloride and pyridine gives the cyclohexanol (XI), which is methylated by means of methyl iodide and NaH to yield the dimethoxy derivative (XII). The cleavage of the trityl group of (XII) by means of HCl in methanol affords the methanol derivative (XIII), which is oxidized by means of DMP to the corresponding carbaldehyde (XIV). The condensation of (XIV) with 2(S)-methyl-5-(trimethylsilyl)-4-pentynyl iodide (XV) by means of t-BuLi and MgBr2 provides the acetylenic alcohol (XVI), which is methylated with methyl iodide and NaH giving the trimethoxy derivative (XVII). The hydrolysis of the acetal group of (XVII) with Ac-OH yields the hemiacetal (XVIII), which is olefinated with the phosphorane (XIX) in refluxing benzene to afford the unsaturated tridecanoic ester (XX). The reduction of (XX) with DIBAL provides the unsaturated diol (XXI), which is submitted to an asymmetric dihydroxylation by means of Ti(O-iPr)4, (+)-diethyl tartrate and tert-butyl hydroperoxide to give the chiral tetrahydropyran diol (XXII). The iodination of the triple bond of (XXII) with AlMe3, Cp2ZrCl2 and iodine yields the iodovinyl compound (XXIII), which is protected by means of Tbdms-Cl, DMAP and imidazole to afford the silylated compound (XXIV). The condensation of (XXIV) with the intermediate spiroenone (IX) by means of t-BuLi provides the open chain intermediate (XXV).