New Applications of the Imine-Ketenimine Intramolecular [2+2] Cycloaddition Reaction: Highly Stereocontrolled Synthesis of Azeto[1,2-a]pyrimidines
作者:Mateo Alajarín、Angel Vidal、Raúl-Angel Orenes
DOI:10.1002/1099-0690(200212)2002:24<4222::aid-ejoc4222>3.0.co;2-m
日期:2002.12
functionalities are linked by an allylic tether connecting the imino and ketenimino nitrogen atoms, undergo a formal intramolecular [2+2] cycloaddition to yield azeto[1,2-a]pyrimidines 8. When enantiotopic ketenimine and imine fragments are combined, the resulting azeto[1,2-a]pyrimidines 8e−i contain two stereogenic carbon atoms C-6 and C-7, and the cycloaddition takes place with complete diastereoselectivity
亚氨基-烯酮亚胺 7,其中反应性官能团通过连接亚氨基和烯酮亚胺氮原子的烯丙基系链连接,经过正式的分子内 [2+2] 环加成生成氮杂 [1,2-a] 嘧啶 8。和亚胺片段结合,所得的氮杂[1,2-a]嘧啶8e-i含有两个立体碳原子C-6和C-7,并且环加成以完全非对映选择性发生,有利于顺式非对映异构体。这种方法也已应用于一些 azeto [1,2-a][1,3] 噻唑并 [4,5-d] 嘧啶 16 的制备,这是一种新的稠合杂环系统的代表性例子。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002)