作者:Maria Krenn、Ernst Urban
DOI:10.1007/s706-002-8242-9
日期:2002.2
A structurally simplified analogue of the antibiotic (+)-heptelidic acid was synthesized in ten steps with an overall yield of 9%. Key step was a conjugate addition of a silyl protected vinylcuprate to an asymmetrically shielded enoate, which gave an adduct as a single diastereomer. Transesterification in the presence of triethylamine allowed a selective cleavage of the chiral auxiliary and afforded
十个步骤合成了抗生素(+)-庚二酸的结构简化的类似物,总收率为9%。关键步骤是将甲硅烷基保护的乙烯基铜酸酯共轭添加到不对称保护的烯酸酯中,从而得到加合物,为单一的非对映异构体。在三乙胺存在下的酯交换反应使手性助剂选择性裂解,得到对映体纯的甲基酯。使用四步反应序列,将该易于烯化的β-酮酸酯转化为 反式 构型的亚甲基衍生物。最后,通过内酯环的形成和四个步骤的连续氧化,可以从亚甲基衍生物获得所需的环氧内酯。