合成路线1

In a different procedure, reduction of methyl 2-methyl-2-pentenoate (XXXVIII) with LiAlH4 afforded the allylic alcohol (XXXIX). Sharpless asymmetric epoxidation of (XXXIX) provided the chiral epoxy alcohol (XL), which was subsequently esterified with benzoyl chloride, yielding the epoxy benzoate (XLI). Reduction of (XLI) with LiAlH4 furnished diol (XLII). After protection of the primary alcohol of (XLII) as the benzyl ether (XLIII), its tertiary hydroxyl group was alkylated with iodomethane to give the methoxy derivative (XLIV). Hydrogenolysis of the benzyl ether group of (XLIV) over Pearlman's catalyst, followed by oxidation of the resultant alcohol (XLV) with pyridinium chlorochromate, led to aldehyde (XLVI). This was condensed with p-toluenesulfinamide (XLVII) in the presence of titanium ethoxide producing the sulfinimide (XLVIII). Diastereoselective condensation of N-Boc-2-(tert-butyldimethylsilyloxy)pyrrole (XLIX) with the chiral sulfinimide (XLVIII) gave rise to the pyrrolidone adduct (L). Copper-catalyzed conjugate addition of propenylmagnesium bromide to the unsaturated lactam (L) provided the (Z)-propenyl pyrrolidinone (LI). Introduction of a cyano group to give (LII) was accomplished by lactam reduction with DIBAL followed by treatment with MeOH and PPTS and cyanide addition as above.