Rhodium(<scp>iii</scp>)-catalyzed cascade oxidative annulation reactions of aryl imidazolium salts with alkynes involving multiple C–H bond activation
作者:Qingmei Ge、Bin Li、Haibin Song、Baiquan Wang
DOI:10.1039/c5ob00823a
日期:——
This provides a new application of NHCs as directing groups and substrates in the synthesis of fused N-heterocyclic compounds. The N-substituting group of the benzo[ij]imidazo[2,1,5-de]quinolizinium salts could be removed successfully with pyridine to afford benzo[ij]imidazo[2,1,5-de]quinolizines in excellent yields. Moreover, some of the benzo[ij]imidazo[2,1,5-de]quinolizinium salts exhibit intense
在[Cp * RhCl 2 ] 2和Cu(OAc)2 ·H 2 O的存在下,芳基咪唑鎓盐与炔的级联氧化环化反应有效地进行,得到取代的咪唑并[1,2- a ]-喹啉鎓盐和苯并[ ij ]咪唑[2,1,5- de]喹啉鎓盐。反应是通过正常和异常的N-杂环卡宾(NHC)定向的环金属化,炔烃插入Rh-C键以及还原性消除烯基和NHC配体而进行的。该反应具有不对称炔烃的高度区域选择性,并且可以通过控制反应条件来逐步实现。这提供了NHCs作为稠合N-杂环化合物合成中的导向基团和底物的新应用。苯并[ ij ]咪唑并[2,1,5- de ]喹啉鎓盐的N-取代基可以用吡啶成功地去除,从而以优异的收率得到苯并[ ij ]咪唑并[2,1,5- de ]喹啉嗪。此外,一些苯并[ ij]咪唑并[2,1,5- de ]喹啉鎓盐显示出强荧光,这可能在有机电子材料中有用。