A highly stereoselective approach to novel 2,2,4-substituted pyrrolidines by halocylization: key intermediates towards syntheses of nitrogen analogs of Noxafil®
作者:Jinping L McCormick、Rebecca Osterman、Tze-Ming Chan、Pradip R Das、Birendra N Pramanik、Ashit K Ganguly、Viyyoor M Girijavallabhan、Andrew T McPhail、Anil K Saksena
DOI:10.1016/j.tetlet.2003.08.114
日期:2003.10
A convenient synthesis of novel 2,2,4-trisubstituted pyrrolidines via stereoselective 5-exo iodocyclization of the 2,2-disubstituted olefins 8 and 9 is described. Single crystal X-ray analysis of the oxazolidinone 15 confirmed the relative stereochemistry in this cyclization. As observed earlier in the formation of 2,2,4-trisubstituted tetrahydrofurans, the presence of a bulky aryl substituent on the
描述了通过2,2-二取代的烯烃8和9的立体选择性5-外位碘化环方便地合成新的2,2,4-三取代的吡咯烷。恶唑烷酮15的单晶X射线分析证实了该环化反应的相对立体化学。如早先在形成2,2,4-三取代的四氢呋喃中所观察到的,烯烃上庞大的芳基取代基的存在似乎指导了这些卤代环化反应的立体化学结果。