Copper(II)-Catalyzed C–H Nitrogenation/Annulation Cascade of Ketene <i>N</i>,<i>S</i>-Acetals with Aryldiazonium Salts: A Direct Access to <i>N</i><sup>2</sup>-Substituted Triazole and Triazine Derivatives
作者:Ping Wu、Yuan He、Hongmei Wang、Yong-Gui Zhou、Zhengkun Yu
DOI:10.1021/acs.orglett.9b04335
日期:2020.1.3
Direct synthesis of N2-substituted triazole and triazine derivatives has been a challenge in N-heterocyclic chemistry. Under copper(II) catalysis ketene N,S-acetals, that is, alkylthio-substituted enaminones, efficiently reacted with aryldiazonium salts to allow the regioselective generation of functionally diverse N2-substituted 1,2,3-triazoles and 2,3-dihydro-1,2,4-triazines. The oxidant and base-dependent
N 2-取代的三唑和三嗪衍生物的直接合成一直是N-杂环化学中的挑战。在铜(II)催化下,烯酮N,S-乙缩醛(即烷硫基取代的烯胺酮)与芳基重氮盐有效反应,从而可以选择性选择性地生成功能多样的N2-取代的1,2,3-三唑和2,3-二氢键-1,2,4-三嗪。氧化剂和碱依赖性反应分别产生五元和六元的N-杂环产物。合成方案具有宽泛的底物范围,在温和条件下具有良好的官能团耐受性。机理研究表明,反应是通过烯基偶氮/亚氨基中间体进行的。