Four Mechanisms in the Reactions of 3-Aminopyrrole with 1,3,5-Triazines: Inverse Electron Demand Diels–Alder Cycloadditions vs S<sub>N</sub>Ar Reactions via Uncatalyzed and Acid-Catalyzed Pathways
作者:Michael De Rosa、David Arnold、Douglas Hartline
DOI:10.1021/jo4012915
日期:2013.9.6
Reaction of 3-aminopyrrole with seven 1,3,5-triazines was studied in a one-step reaction (in situ formation of 3-aminopyrrole) and a two-step reaction (using the tetraphenylborate salt and an amine base). An inverse-electron demand Diels–Alder reaction (IEDDA) was observed with R1 = CF3, CO2Et, and H with the formation of 5H-pyrrolo[3,2-d]pyrimidine derivatives. SNAr was observed when 2,4,6-trifluoro-
在一步反应(原位形成3-氨基吡咯)和两步反应(使用四苯基硼酸盐和胺碱)中研究了3-氨基吡咯与七个1,3,5-三嗪的反应。观察到反电子需求Diels-Alder反应(IEDDA),R 1 = CF 3,CO 2 Et和H,形成5 H-吡咯并[3,2- d ]嘧啶衍生物。小号Ñ当2,4,6-三氟或2,4,6-三氯-1,3,5-三嗪,使用-1,3,5-三嗪的是有离去基团,观察到的Ar。如果存在过量的1,3,5-三嗪,则初始S NAr产物在酸和水的存在下与另一当量的1,3,5-三嗪进一步反应,得到含有三个连接的杂环的化合物。在R 1= C 6 H 5和OCH 3下未观察到反应。提出了四种机理来解释实验结果:未催化和酸催化的逆电子需求Diels-Alder级联导致环加成,以及未催化和酸催化的S N Ar反应分别导致单取代和双取代产物。当任一反应物的反应性降低时,酸催化是一个因素。