Assembly of 1,2,3,4-Tetrahydropyrrolo[1,2-<i>a</i>]pyrazines via the Domino Reaction of 2-Imidazolines and Terminal Electron-Deficient Alkynes
作者:Nikita E. Golantsov、Alexandra S. Golubenkova、Alexey A. Festa、Alexey V. Varlamov、Leonid G. Voskressensky
DOI:10.1021/acs.joc.1c02930
日期:2022.3.4
4-tetrahydropyrrolo[1,2-a]pyrazines has been realized. A pseudo-three-component reaction of 2-imidazolines with terminal electron-deficient alkynes (2 equiv) first generates imidazolidines, containing an N-vinylpropargylamine fragment. The latter can then undergo a base-catalyzed domino aza-Claisen rearrangement/cyclization reaction sequence, simultaneously constructing pyrrole and pyrazine rings. The process
2-咪唑啉转化为1,2,3,4-四氢吡咯并[1,2- a ]吡嗪已经实现。2-咪唑啉与末端缺电子炔烃(2 equiv)的拟三组分反应首先生成含有N-乙烯基炔丙基胺片段的咪唑烷。然后后者可以进行碱催化的多米诺氮杂-克莱森重排/环化反应序列,同时构建吡咯和吡嗪环。该工艺适用于广泛的底物范围,提供 pyrrolo [1,2- a]吡嗪具有良好至极好的产率 (45–90%)。这种两步法可以一锅法进行,而不会显着降低产量。值得注意的是,还开发了用于引入两种不同炔烃的三组分方案。