Visible Light-Promoted Metal-Free C-H Activation: Diarylketone-Catalyzed Selective Benzylic Mono- and Difluorination
Ji-Bao Xia, Chen Zhu and Chuo Chen*
*Division of Chemistry, Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, United States, Email: Chuo.ChenUTSouthwestern.edu
J.-B. Xia, C. Zhu, C. Chen, J. Am. Chem. Soc., 2013, 135, 17494-17500.
DOI: 10.1021/ja410815u (free Supporting Information)
Visible light activates diarylketone catalysts to abstract a benzylic hydrogen atom selectively, which enables an operationally simple direct fluorination of benzylic C-H groups in the presence of a fluorine radical donor. 9-Fluorenone catalyzes benzylic C-H monofluorination, while xanthone catalyzes benzylic C-H difluorination.
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