Visible-Light-Promoted [2 + 2 + 2] Cyclization of Alkynes with Nitriles to Pyridines Using Pyrylium Salts as Photoredox Catalysts
作者:Kuai Wang、Ling-Guo Meng、Lei Wang
DOI:10.1021/acs.orglett.7b00292
日期:2017.4.21
regioselective [2 + 2 + 2] cyclization of aromatic alkynes with nitriles is developed for the preparation of 2,3,6-trisubstituted pyridines under visible-light irradiation using a pyrylium salt as the photoredox catalyst. This cycloaddition is achieved through a photooxidative single-electron-transfer process at room temperature and under metal-free conditions. A variety of aromatic alkynes and nitriles
开发了具有腈的高度区域选择性的[2 + 2 + 2]芳族炔烃环化反应,用于在吡咯鎓盐作为光氧化还原催化剂的可见光照射下制备2,3,6-三取代的吡啶。该环加成反应是通过在室温和无金属条件下进行光氧化单电子转移过程实现的。使用多种芳族炔烃和腈以高收率提供环氧化产物。