合成路线1

The asymmetric reduction of 5-(4-methoxybenzyloxy)-3-oxopentanoic acid methyl ester (XXXIII) with H2 over a chiral Ru catalyst gives the chiral hydroxyester (XXXIV), which is alkylated by means of allyl bromide (XXXV) and LDA to yield the chiral 2-allyl-3-hydroxypentanoic ester (XXXVI). The reduction of (XXXVI) with LiAlH4, and then with DDQ affords the 1,3-dioxan-4-ylethanol (XXXVII), which is treated with NIS, NaHCO3 and reduced with DIBAL to afford the iodomethyl tetrahydrofuran (XXXVIII). The oxidation of the primary OH group of (XXXVIII) with oxalyl chloride provides the carbaldehyde (XXXIX), which is condensed with the propenylstannane (XL) by means of BF3/Et2O in dichloromethane to give the unsaturated alcohol (XLI). The protection of the OH group of (XLI) with TipsOTf yields the unsaturated silyl ether (XLII), which is ozonolyzed by means of O3, pyridine and Me2S to afford the carbaldehyde (XLIII). The condensation of (XLIII) with the chiral intermediate 2-bromovinyl cyclohexane (XVIII) by means of tBuLi and MgBr2 provides the alcohol (XLIV), which is esterified with 1-(tert-butoxycarbonyl)piperidine-2(S)-carboxylic acid (XLV) by means of DCC to give the expected ester (XLVI). The reaction of (XLVI) with Zn and NH4Cl yields the chiral alpha-allyl alcohol (XLVII), which is oxidized by means of oxalyl chloride to afford the corresponding carbaldehyde (XLVIII).