Synthesis of Furo[3,2-<i>b</i>]quinolines and Furo[2,3-<i>b</i>:4,5-<i>b′</i>]diquinolines through [4 + 2] Cycloaddition of Aza-<i>o</i>-Quinone Methides and Furans
作者:Lu Lei、Yi-Yun Yao、Li-Juan Jiang、Xiuqiang Lu、Cui Liang、Dong-Liang Mo
DOI:10.1021/acs.joc.9b02953
日期:2020.3.6
An approach for the construction of furo[3,2-b]quinolines and furo[2,3-b:4,5-b']diquinolines is developed through a metal-free [4 + 2] cycloaddition of easily available in situ generated aza-o-quinone methides and furans. The reaction tolerates a wide range of aza-o-quinone methides and substituted furans to afford the corresponding dihydro- or tetrahydrofuroquinolines in good to excellent yields.
通过无金属的[4 + 2]环加成反应,开发了一种呋喃[3,2-b]喹啉和呋喃[2,3-b:4,5-b']二喹啉的构建方法,该方法容易就地获得生成氮杂邻醌甲基化物和呋喃。该反应可耐受各种氮杂-邻-醌甲基化物和取代的呋喃,从而以良好或优异的产率提供相应的二氢-或四氢呋喃喹啉。机理研究表明,该反应涉及协同的[4 + 2]环加成途径,并且显示出对呋喃环的环加成具有很高的区域选择性。本方法的特点是反应条件温和,呋喃脱芳香化,区域选择性和非对映选择性高,可按克缩放的制剂以及呋喃喹啉的多样性。