Open AccessDavis–Beirut Reaction: A Photochemical Brønsted Acid Catalyzed Route to N-Aryl 2H-Indazoles
Author(s) -
Niklas Kraemer,
Clarabella J. Li,
Jie Zhu,
Julio M. Larach,
Ka Yi Tsui,
Dean J. Tantillo,
Makhluf J. Haddadin,
Mark J. Kurth
Publication year - 2019
Publication title -
organic letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.94
H-Index - 239
eISSN - 1523-7060
pISSN - 1523-7052
DOI - 10.1021/acs.orglett.9b02213
Subject(s) - chemistry , aryl , catalysis , brønsted–lowry acid–base theory , nitroso , alkyl , imine , nitro , photochemistry , combinatorial chemistry , medicinal chemistry , organic chemistry
The Davis-Beirut reaction provides access to 2 H -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 for accessing N -aryl targets. Anilines and alkyl amines give different outcomes under optimized conditions; the proposed mechanism was studied using quantum chemical calculations.