Investigation of the [1,5]-hydride shift as a route to nitro-Mannich cyclisations
作者:James C. Anderson、Chia-Hao Chang、Mérina K. Corpinot、Michael Nunn、Oliver J. Ware
DOI:10.1016/j.tet.2019.130663
日期:2019.11
Conditions were found for the [1,5]-hydride shift nitro-Mannich reaction that led to the synthesis of 2,3-disubstituted tetrahydroquinolines. Two simple cyclic amine substrates gave diastereomerically pure rearranged products in 65 and 90% yields by refluxing in HFIP. A more general procedure used Gd(OTf)3 as a catalyst and successfully rearranged other cyclic and acyclic amines in 42–84% yield with
发现了[1,5]-氢化物转移硝基-曼尼希反应的条件,该条件导致了2,3-二取代的四氢喹啉的合成。通过在HFIP中回流,两种简单的环状胺底物可分别以65%和90%的收率得到非对映体纯的重排产物。一种更通用的方法是使用Gd(OTf)3作为催化剂,并以42:84%的产率成功重排其他环状和无环胺,非对映体比例为75:25至> 95:5,有利于抗非对映异构体(9个实例) 。含硫杂环的两个实例给出的产率较低,分别为9%和25%。吸电子取代基显示出对反应成功具有有害作用。结果表明,[1,5]-氢化物转移硝基-曼尼希反应相对于中间体亚胺离子的稳定性有局限性。