Reaction of α-Diazopyrroles with Enamines: Synthesis of Pyrrolo[2,1-<i>c</i>][1,2,4]triazines and α-(1,2,5-Triazapenta-1,3-dienyl)pyrroles
作者:Nikita A. Kaminskiy、Ekaterina E. Galenko、Mariya A. Kryukova、Mikhail S. Novikov、Alexander F. Khlebnikov
DOI:10.1021/acs.joc.2c01102
日期:2022.8.5
temperature to give either (4+2)-cycloaddition–dehydroamination cascade products, pyrrolo[2,1-c][1,2,4]triazines, or azo coupling products. The reaction was used for the synthesis of functionalized ortho-fused heterocycles with new tetrahydrobenzo[e]pyrrolo[2,1-c][1,2,4]triazine and tetrahydro-6H-cyclohepta[e]pyrrolo[2,1-c][1,2,4]triazine frameworks. Unstable azo compounds, 2-[(2-aminovinyl)diazenyl]pyrroles
α-重氮吡咯在室温下选择性地与烯胺反应生成 (4+2)-环加成-脱氢胺级联产物、吡咯并[2,1- c ][1,2,4]三嗪或偶氮偶联产物。该反应用于与新的四氢苯并[ e ]吡咯并[2,1- c ][1,2,4]三嗪和四氢-6H-环庚[ e ]吡咯并[2,1]合成官能化的邻位稠合杂环-c _][1,2,4]三嗪框架。从四氢萘酮或无环酮的烯胺中获得不稳定的偶氮化合物,2-[(2-氨基乙烯基)二氮烯基]吡咯。根据密度泛函理论计算,α-重氮吡咯与烯胺的 (4+2)-环加成通过两性离子中间体以非协调方式进行,中间体环化为吡咯并三嗪或竞争性 1,5-质子转变导致形成偶氮偶联产物。