Synthesis of malhamensilipin A exploiting iterative epoxidation/chlorination: experimental and computational analysis of epoxide-derived chloronium ions.
Synthesis of malhamensilipin A exploiting iterative epoxidation/chlorination: experimental and computational analysis of epoxide-derived chloronium ions.
复制标题
Malhamensilipin的合成一种剥削性迭代环氧化/氯化：环氧衍生的氯基离子的实验和计算分析。
DOI：
10.1039/c6sc03012b
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发表时间：
2016-12-11
期刊：
影响因子：
8.4
通讯作者：
Denton RM
中科院分区：
文献类型：
--
作者：
Saska J;Lewis W;Paton RS;Denton RM
我们报道了一种基于环氧化/氯化迭代策略的12步催化不对称选择性的malhamensilipin A（3）的缩甲醛合成。本文报道了由（E）-2-十一烯醛催化对映选择性的12步形式合成malhamensilipin A（3）及其非对映异构体类似物的方法。收敛合成依赖于迭代的环氧化和磷（V）介导的脱氧二氯化反应以及钛介导的环氧化物打开以构建C11-C16立体六元。后一种转化发生时，无论母体环氧化物的C13构型如何，都具有非常高的立体保留水平，这意味着γ-或δ-氯原子的邻位协助，以及分别形成氯离子或氯离子。的氯离子中间体的计算分析提供了支持的参与chlorolorphinium离子，而潜在的resultanium离子被认为是不太可能的中间体的基础上，他们更大的碳阳离子字符。
We report a 12-step catalytic enantioselective formal synthesis of malhamensilipin A (3) based upon an iterative epoxidation/chlorination strategy. We report a 12-step catalytic enantioselective formal synthesis of malhamensilipin A (3) and diastereoisomeric analogues from (E)-2-undecenal. The convergent synthesis relied upon iterative epoxidation and phosphorus(v)-mediated deoxydichlorination reactions as well a titanium-mediated epoxide-opening to construct the C11–C16 stereohexad. The latter transformation occurred with very high levels of stereoretention regardless of the C13 configuration of the parent epoxide, implicating anchimeric assistance of either the γ- or δ-chlorine atoms, and the formation of chloretanium or chlorolanium ions, respectively. A computational analysis of the chloronium ion intermediates provided support for the involvement of chlorolanium ions, whereas the potential chloretanium ions were found to be less likely intermediates on the basis of their greater carbocationic character.