AbstractIn recent decades, many efforts have been devoted to studying reactions catalyzed in nanoconfined spaces. The most impressive aspect of catalysis in nanoconfined spaces is that the reactivity of the molecules can be smartly driven to disobey classical behavior. A green and efficient three‐component aza‐Darzens (TCAD) reaction using a catalytic amount of γ‐cyclodextrins (CDs) in water has been developed to synthesize N‐phenylaziridines. CDs effectively performed this reaction in an environmentally friendly setting, achieving good yields. The same reaction was then performed using polymeric γ‐CD such as a γ‐cyclodextrin polymer crosslinked (GCDPC) with epichlorohydrin, a sponge‐like macroporous γ‐cyclodextrin‐based cryogel (GCDC), and a γ‐cyclodextrin‐based hydrogel (GCDH). The homogeneous and heterogeneous catalyst recovery was then studied, and it was proved to be easily recycled several times without relevant activity loss. Water, as a unique and eco‐friendly reaction medium, has been utilized for the first time, to the best of our knowledge, in this reaction. The inclusion of the reagents in CDs has been studied and rationalized by NMR spectroscopy experiments and molecular modeling calculations. The credit of the presented protocol includes good yields and catalyst reusability and precludes the use of organic solvents.
摘要 近几十年来,人们致力于研究在纳米封闭空间中催化的反应。纳米封闭空间催化反应最令人印象深刻的一点是,分子的反应性可以被巧妙地驱动,从而违背经典行为。利用催化量的γ-环糊精(CDs)在水中合成 N-苯基氮丙啶,开发出了一种绿色、高效的三组分氮杂-达先(TCAD)反应。CDs 在环保的环境下有效地完成了这一反应,并获得了良好的产率。随后,使用聚合物 γ-CD 进行了相同的反应,如与环氧氯丙烷交联的 γ-环糊精聚合物 (GCDPC)、海绵状大孔 γ-环糊精基冷凝胶 (GCDC) 和 γ-环糊精基水凝胶 (GCDH)。然后对催化剂的均相和异相回收进行了研究,结果表明催化剂可以多次轻松回收,且不会造成相关活性损失。据我们所知,水作为一种独特且环保的反应介质,首次被用于该反应。核磁共振光谱实验和分子模型计算对 CD 中试剂的加入进行了研究和合理化。该方案的优点包括产率高、催化剂可重复使用以及无需使用有机溶剂。