Synthesis of Indazolones via Friedel-Crafts Cyclization of Blocked (Masked) N-Isocyanates
Eslam B. Elkaeed, Jing An and André M. Beauchemin*
*Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON K1N 6N5, Canada, Email: andre.beaucheminuottawa.ca
E. B. Elkaeed, J. An, A. M. Beauchemin, J. Org. Chem., 2017, 82, 9890-9897.
DOI: 10.1021/acs.joc.7b01607 (free Supporting Information)
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The use of blocked (masked) N-isocyanate precursors enables the formation of indazolones by Friedel-Crafts cyclization. Substrate synthesis has also been improved using a copper-catalyzed arylation of phenyl carbazates with pentavalent bismuth reagents that is compatible with the hemilabile OPh blocking group.
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proposed reaction pathway