Davis–Beirut Reaction: A Photochemical Brønsted Acid Catalyzed Route to <i>N</i>-Aryl 2<i>H</i>-Indazoles
作者:Niklas Kraemer、Clarabella J. Li、Jie S. Zhu、Julio M. Larach、Ka Yi Tsui、Dean J. Tantillo、Makhluf J. Haddadin、Mark J. Kurth
DOI:10.1021/acs.orglett.9b02213
日期:2019.8.2
The Davis–Beirut reaction provides access to 2H-indazoles from aromatic nitro compounds. However, N-aryl targets have been traditionally challenging to access due to competitive alternate reaction pathways. Previously, the key nitroso imine intermediate was generated under alkaline conditions, but as reported here, the photochemistry of o-nitrobenzyl alcohols empowered Brønsted acid catalyzed conditions
Davis-Beirut 反应可以从芳香硝基化合物中获得 2 H-吲唑。然而,由于竞争性的替代反应途径, N-芳基靶标传统上很难获得。以前,关键的亚硝基亚胺中间体是在碱性条件下生成的,但正如本文所报道的,邻硝基苯甲醇的光化学赋予了布朗斯台德酸催化条件来接近N-芳基目标。苯胺和烷基胺在优化条件下会产生不同的结果;使用量子化学计算研究了所提出的机制。