Copper-Mediated Domino Cyclization/Trifluoromethylation/Deprotection with TMSCF3: Synthesis of 4-(Trifluoromethyl)pyrazoles
Quande Wang, Lisi He, Kin Keung Li and Gavin Chit Tsui*
*Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China, Email: gctsuicuhk.edu.hk
Q. Wang, L. He, K. K. Li, G. C. Tsui, Org. Lett., 2017, 19, 658-661.
DOI: 10.1021/acs.orglett.6b03822 (free Supporting Information)
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A copper-mediated remarkable domino sequence of cyclization, trifluoromethylation, and detosylation provides 4-(trifluoromethyl)pyrazoles from readily accessible α,β-alkynic tosylhydrazones and commercially available trifluoromethyltrimethylsilane as the CF3 source. The reaction conditions are mild and convenient with good functional group compatibility, at room temperature in air.
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