New Syntheses of E7389 C14−C35 and Halichondrin C14−C38 Building Blocks: Double-Inversion Approach
作者:Dae-Shik Kim、Cheng-Guo Dong、Joseph T. Kim、Haibing Guo、Jian Huang、Paolo S. Tiseni、Yoshito Kishi
DOI:10.1021/ja9058475
日期:2009.11.4
sequential use of catalytic asymmetric Cr-mediated coupling reactions, E7389 C14-C35 and halichondrin C14-C38 building blocks have been stereoselectively synthesized. The C19-C20 bond is first formed via the catalytic asymmetric Ni/Cr-mediated coupling, i.e., 8 + 9 --> 10 (90%; dr = 22:1), in which vinyl iodide 8 is used as the limiting substrate. The C23-C24 bond is then formed via the catalytic asymmetric
通过连续使用催化不对称 Cr 介导的偶联反应,已立体选择性地合成了 E7389 C14-C35 和软海绵素 C14-C38 构建块。C19-C20 键首先通过催化不对称 Ni/Cr 介导的偶联形成,即 8 + 9 --> 10 (90%; dr = 22:1),其中乙烯基碘 8 作为限制底物. 然后通过催化不对称 Co/Cr 介导的偶联形成 C23-C24 键,即 13 + 14 --> 4 (82%; dr = 22:1),其中 14 中的烷基碘键是选择性的在乙烯基碘键上活化。采用催化不对称 Ni/Cr 介导的反应将 C14-C26 链段 19 与 E7389 C27-C35 链段 20(91%;dr = >55:1)偶联。在该合成中,C23-O 键是通过双反转过程立体选择性构建的,即 21 --> 22,以 84% 的收率提供 E7389 C14-C35 结构单元 22。相同的合成序列已被用于合成软海绵素