Selective Macrocycle Formation in Cavitands
Selective Macrocycle Formation in Cavitands
复制标题
Cavitands 中的选择性大环形成
DOI：
10.1021/jacs.0c12302
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发表时间：
2021
影响因子：
15
通讯作者：
Rebek, Julius
中科院分区：
文献类型：
--
作者：
Yang, Ji-Min;Yu, Yang;Rebek, Julius
传统的长链线性前体的端到端环化是困难的，而且往往是不可预测的，因为大环闭合的不利熵允许不希望的分子间反应竞争。本文将空腔体应用于长链α，ω-二醛在水溶液中的选择性醛醇/脱水反应。疏水力驱使二醛以折叠的构象进入空腔体，与在散装溶液中观察到的分子间反应相比，更有利于大环化反应。大环醛醇反应产物的分离率高（30-85%），范围广（11 - 17元环）。与传统模板在其组装的宿主体内成为客人不同，空腔体的角色相反，类似于生物催化中的情况——模板是客人的宿主，经历辅助反应过程。
The traditional end-to-end cyclization of long-chain linear precursors is difficult and often unpredictable because the unfavorable entropy of macrocyclic closure allows undesired intermolecular reactions to compete. Here, we apply cavitands to the selective intramolecular aldol/dehydration reaction of long-chain α,ω-dialdehydes in aqueous solution. Hydrophobic forces drive the dialdehydes into the cavitands in folded conformations and favor macrocyclization reactions over intermolecular reactions observed in bulk solution. The macrocyclic aldol reaction products are isolated in good yields (30–85%) over a wide range (11 to 17-membered rings). Unlike conventional templates that become guests inside their assembled hosts, cavitands reverse the roles and resemble the situation in biological catalysis—the templates are hosts for guests undergoing the assisted reaction processes.