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 fromaromatic 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 Reaction: Alkoxide versus Hydroxide Addition to the Key <i>o</i>-Nitrosoimine Intermediate
作者:Jie S. Zhu、Matthew R. Duong、Andrew P. Teuthorn、Julia Y. Lu、Jung-Ho Son、Makhluf J. Haddadin、Mark J. Kurth
DOI:10.1021/acs.orglett.8b00036
日期:2018.3.2
Reaction options, alkoxide vs hydroxide vs amine addition to the key intermediate (o-nitrosoimine) generated in the Davis–Beirut reaction of an o-nitrobenzylamine substrate, are reported to explain the nucleophilic addition selectivity of this one-pot indazole-forming process. The hydroxide addition/deprotection pathway as well as the fate of the resulting o-nitrosobenzaldehyde were both uncovered