Asymmetric Crotylation Reactions in Synthesis of Polypropionate-Derived Macrolides: Application to Total Synthesis of Oleandolide
作者:Tao Hu、Norito Takenaka、James S. Panek
DOI:10.1021/ja020853m
日期:2002.10.1
details of a convergent asymmetric synthesis of oleandolide (1), the aglycon of the macrolide antibiotic oleandomycin, is described. The synthesis has been achieved through the assembly and coupling of the left- and right-hand subunits 12 and 38, respectively. These subunits were prepared from chiral silane-based asymmetric crotylation reactions to control the stereochemical relationships. The left-
描述了大环内酯类抗生素 oleandomycin 的苷元 oleandolide (1) 的收敛不对称合成的完整细节。该合成是通过分别组装和耦合左侧和右侧亚基 12 和 38 来实现的。这些亚基由基于手性硅烷的不对称巴豆化反应制备,以控制立体化学关系。通过锌中间体 40 和三氟甲磺酸乙烯酯 38 之间的 Pd(0) 催化的 sp3-sp2 交叉偶联反应,将左手和右手亚基(C1-C7 和 C8-C14)结合在一起,得到 27。该产品在山口条件下转化为seco酸42a并环化为内酯35。然后将该材料用间氯过苯甲酸 (m-CPBA) 环氧化以安装正确的 C8 环氧化物作为单一非对映异构体,