Department of Chemistry, University of Illinois at Chicago, 845 W Taylor St., MC 111, Chicago, IL, 60607, USA.
Department of Process Research & Development, Merck & Co., Inc., 126 Lincoln Ave, Rahway, NJ, 07065, USA.
Chemistry. 2023 May 26;29(30):e202300551. doi: 10.1002/chem.202300551. Epub 2023 Apr 17.
The roles of substituent and solvent effects in promoting the 4π electrocyclization of N-alkenylnitrones to give azetidine nitrones have been investigated by experimental examination of relative rates, activation energies, and linear free energy relationships. These transformations are synthetically important because they favor the formation of a strained heterocyclic ring with imbedded functionality and stereochemical information for versatile derivatization. Mechanistic investigations, including Hammett studies, solvent-dependent Eyring studies, and solvent isotope effects, provide insight into the steric and electronic factors that control these electrocyclizations and identify trends that can be used to advance this approach towards the rapid synthesis of complex azetidines.
通过对相对速率、活化能和线性自由能关系的实验考察，研究了取代基和溶剂效应对促进 N-烯丙基硝酮的 4π 电环化生成氮杂环丁烷硝酮的作用。这些转化在合成上很重要，因为它们有利于形成具有嵌入式功能和立体化学信息的应变杂环，可用于各种衍生化。包括哈米特研究、溶剂依赖性艾林研究和溶剂同位素效应在内的机理研究，提供了对控制这些电环化的立体和电子因素的深入了解，并确定了可用于推进这种方法快速合成复杂氮杂环丁烷的趋势。
