<i>Lewis</i>
Acid‐Mediated Ring Contraction of 2,4‐Diaryl‐2,3‐dihydro‐1
<i>H‐</i>
1,5‐benzodiazepines: Access to 2‐Aryl‐1‐styrylbenzimidazoles
作者:Mengyao Zhang、Qiuyue Wu、Jiaxi Xu
DOI:10.1002/hlca.202200143
日期:——
3-dihydro-1H-1,5-benzodiazepines readily undergo a ring contraction to generate 2-aryl-1-styrylbenzimidazoles in the presence of some Lewis acids. Copper acetate shows high efficiency compared with other Lewis acids. The ring contraction includes Lewis acid-catalyzed intramolecular addition, ammonium-induced ring-opening of the generated four-membered azetidine ring, deprotonation, and amine-promoted nucleophilic
2,4-Diaryl-2,3-dihydro-1 H -1,5-benzodiazepines 很容易在某些路易斯酸存在的情况下发生环收缩,生成 2-aryl-1-styrylbenzimidazole 。与其他路易斯酸相比,醋酸铜显示出高效率。环收缩包括路易斯酸催化的分子内加成、铵诱导的四元氮杂环丁烷环开环、去质子化和胺促进的亲核苯乙烯基 1,2-转移和消除。乙酸铜用作路易斯酸、碱和氧化剂。当前的反应提供了一种从容易获得的 2,4-diaryl-2,3-dihydro-1 H-方便地合成 2-aryl-1-styrylbenzimidazole 衍生物的有效方法1,5-苯二氮卓类药物。