Synthetic Studies of Antitumor Macrolide Rhizoxin: Stereoselective Syntheses of the C(1)−C(9) and C(12)−C(26) Subunits
作者:Steven D. Burke、Jian Hong、Joseph R. Lennox、Andrew P. Mongin
DOI:10.1021/jo980754k
日期:1998.10.1
Horner-Wadsworth-Emmons reaction. The central segment 4 and the oxazole chromophore side chain 3 were coupled using another highly stereoselective Horner-Wadsworth-Emmons reaction. Two different lactone subunits [C(1)-C(9) segment 5 and C(3)-C(10) segment 47] were also prepared, employing a thermodynamically controlled diastereotopic group differentiation tactic for establishing the C(5) stereochemistry
描述了一种三重收敛的合成方法,该方法最终完成了大环内酯类抗肿瘤剂Rhizoxin的C(1)-C(9)和C(12)-C(26)亚基的对映选择性合成。中央C(12)-C(20)亚基4是通过猪胰脂肪酶的非对映选择性酶促乙酸15水解,螯合控制的爱尔兰-克莱森重排(10-> 12)结合动力学溴化(12)有效制备的(12) -> 14)和Mitsunobu反演(23-> 26),以引入三个连续的C(15)-C(17)立体中心。C(18)-C(19)三取代(E)-烯烃的形成是通过立体选择性Horner-Wadsworth-Emmons反应实现的。使用另一个高度立体选择性的霍纳-沃兹沃思-埃蒙斯反应将中心链段4和恶唑生色团侧链3偶联。