Key Laboratory of Green Chemistry and Technology, College of Chemistry, Huaxi MR Research Center (HMRRC), Department of Radiology, and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
Guangxi Key Laboratory of Bioactive Molecules Research and Evaluation, School of Pharmacy, Guangxi Medical University, Nanning, China.
Nat Protoc. 2022 Nov;17(11):2494-2516. doi: 10.1038/s41596-022-00722-6. Epub 2022 Aug 31.
Photochemical methods are increasingly being used in organic synthesis. They are especially useful for preparing many compounds that are not readily accessible through thermal or enzymatic reactions. The supramolecular strategy has proved highly promising in recent years for manipulating the stereochemical outcome of chiral photoreactions through relatively strong and long-lasting noncovalent interactions in both ground and excited states. Among the numerous chiral photochemical reactions, photocyclodimerization of 2-anthracenecarboxylate (AC) is the most comprehensively studied supramolecular chiral photoreaction and has essentially become a benchmark reaction for evaluating supramolecular photochirogenesis. Cyclodextrin (CD) derivatives were the earliest and are the most widely applied chiral host for mediating photoreactions. Herein, we use CD-mediated photocyclodimerization of AC as an example to introduce the operation process of supramolecular chiral photoreactions. The protocol includes the following contents: (i) the preparation, purification and characterization of β-CD derivatives; (ii) methods for investigating the host-guest inclusion behavior between AC and β-CD derivatives; (iii) the photochemical reaction operation flow under different solvent and temperature conditions; (iv) chiral high-performance liquid chromatography (HPLC) analyses of the product distribution and enantioselectivity. The protocol is introduced by using representative examples of the synthesis of β-CD derivatives and the manipulation of environmental factors that give excellent regio- and enantioselectivities in the photocyclodimerization of AC. The synthesis and purification of β-CD derivatives require 3-5 d of work. The photoirradiation of AC with β-CD derivatives can be done within 1 h. The product analysis requires 5 h.
光化学方法在有机合成中越来越多地被使用。它们特别适用于制备许多通过热或酶反应不易获得的化合物。近年来，超分子策略在通过相对较强和持久的非共价相互作用来操纵手性光化学反应的立体化学结果方面显示出很高的前景，这些相互作用存在于基态和激发态中。在众多的手性光化学反应中，2-蒽羧酸酯（AC）的光环二聚化是研究最广泛的超分子手性光化学反应，基本上已成为评估超分子光致手性的基准反应。环糊精（CD）衍生物是最早的也是应用最广泛的手性主体，用于介导光反应。在此，我们以 CD 介导的 AC 光环二聚化为例，介绍超分子手性光化学反应的操作过程。该方案包括以下内容：（i）β-CD 衍生物的制备、纯化和表征；（ii）研究 AC 与β-CD 衍生物之间主客体包合行为的方法；（iii）不同溶剂和温度条件下光化学反应的操作流程；（iv）产物分布和对映选择性的手性高效液相色谱（HPLC）分析。该方案通过使用β-CD 衍生物的合成和环境因素操作的代表性实例进行介绍，这些实例在手性光环二聚化 AC 中给出了优异的区域和对映选择性。β-CD 衍生物的合成和纯化需要 3-5 天的工作时间。AC 与β-CD 衍生物的光辐照可以在 1 小时内完成。产物分析需要 5 小时。
