A stereoselective synthesis of asymmetrically substituted calix[4]arenecarbamates
作者:Vyacheslav I. Boyko、Alexander Shivanyuk、Volodymyr V. Pyrozhenko、Roman I. Zubatyuk、Oleg V. Shishkin、Vitaly I. Kalchenko
DOI:10.1016/j.tetlet.2006.08.095
日期:2006.10
Calix[4]arenes bearing a methoxy and an R or S alpha-phenylethylacetamido group at the narrow rim of macrocycles are stereoselectively acylated with 1 equiv of trichloroacetyl isocyanate to give chiral asymmetrically substituted calix[4]arenecarbamates in preparative yields and high diastereomeric excess. (c) 2006 Elsevier Ltd. All rights reserved.
Diastereoselective reaction of 1,3-dihydroxy calixarene with acylisocyanates: new and easy approach for preparing inherently chiral calyx[4]arenes
作者:V. I. Boyko、A. B. Rozhenko、V. V. Pirozhenko、S. V. Shishkina、O. V. Shishkin、V. I. Kalchenko
DOI:10.1007/s11224-015-0706-5
日期:2016.2
The facile method of generating internal chirality into the calixarene with two hydroxy groups at the lower rim via an attached chiral substituent has been proposed. The reaction with acylisocyanates, catalyzed by a small amount of triethylamine, proceeds forming predominantly one of the two possible calixarene carbamates. The best diastereomeric excess (60 %) has been achieved in the reaction of trichloroacyl
已经提出了通过连接的手性取代基在下边缘具有两个羟基的杯芳烃中产生内部手性的简便方法。与酰基异氰酸酯的反应在少量三乙胺的催化下进行,主要形成两种可能的杯芳烃氨基甲酸酯中的一种。在三氯酰基异氰酸酯与被手性苯乙基酰胺部分取代的 1,3-羟基杯芳烃的反应中,已实现最佳非对映体过量 (60%)。三氯乙酰氨基甲酰基杯[4]arenas的单个非对映异构体通过结晶分离,它们的绝对构型通过X射线衍射研究确定。通过量子化学计算预测的 1,3-二羟基杯芳烃结构最受青睐的构象具有非常相似的稳定性。然而,三乙胺分子优选连接到两个可用羟基的一个羟基,提供最有利的加合物,其主要参与与酰基异氰酸酯的反应。这导致观察到的非对映体过量。随后在 NaH 存在下用正丙基溴处理形成的氨基甲酰基并水解烷基化产物很容易提供持久的内部手性杯芳烃。