A General and Stereocontrolled Strategy for the Iterative Assembly of Enantiopure Polypropionate Subunits: Synthesis of the C19−C28 Segment of Rifamycin S from a Single Chiron
作者:Stephen Hanessian、Wengui Wang、Yonghua Gai、Eric Olivier
DOI:10.1021/ja970251g
日期:1997.10.1
stereocontrolled construction of polypropionate stereotriads in high enantio- and diastereomeric purities. The method consists of the stereocontrolled addition of lithium dimethylcuprate to an enantiopure γ-alkoxy-α,β-unsaturated ester, followed by hydroxylation of the corresponding enolate. This leads to an anti/syn orientation of the γ-alkoxy-β-methyl-α-hydroxy ester unit. Chain extension and reiteration
已经开发了一种操作简单的方法,用于立体控制构建高对映和非对映纯度的聚丙酸酯立体三联体。该方法包括将二甲基铜酸锂立体控制加成到对映体纯的 γ-烷氧基-α,β-不饱和酯,然后将相应的烯醇羟基化。这导致γ-烷氧基-β-甲基-α-羟基酯单元的反/顺取向。在适当的功能化后,该过程的链延伸和重复最终导致含有三个连续的具有正确预期绝对构型的聚丙酸酯三联体的 11 碳无环链。该方法依赖于两个基本的键形成反应,涉及连续的 1,2-感应。它通过四个铜酸盐添加和羟基化的迭代循环进行了令人钦佩的立体控制。每次α-羟基化后α-烷氧基的反转允许通过不同构型的立体三联体。因此,四种可能的圣...