Visible‐Light‐Induced Selective Defluoroborylation of Polyfluoroarenes, gem‐Difluoroalkenes, and Trifluoromethylalkenes

• Published in: Angewandte Chemie International Edition Vol. 59; no. 10; pp. 4009 - 4016
• Main Authors: Xu, Wengang, Jiang, Heming, Leng, Jing, Ong, Han‐Wee, Wu, Jie
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 02.03.2020; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Atom economy; Boranes; boryl radical; Catalysis; Catalysts; Chemistry; Chemistry, Multidisciplinary; defluoroborylation; Fluorination; hydrogen atom transfer; Organic compounds; photocatalysis; Physical Sciences; polyfluoroarene; Regioselectivity; Science & Technology; Substrates; ELECTRON; polyfluoroarene; defluoroborylation; COMPLEXES; N-HETEROCYCLIC CARBENES; C-F ACTIVATION; hydrogen atom transfer; FUNCTIONALIZATION; boryl radical; FACILE ACCESS; COUPLING REACTIONS; FLUORINE; CATALYZED BORYLATION; photocatalysis; PHOTOREDOX-CATALYSIS
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201911819

Fluorinated organoboranes serve as versatile synthetic precursors for the preparation of value‐added fluorinated organic compounds. Recent progress has been mainly focused on the transition‐metal catalyzed defluoroborylation. Herein, we report a photocatalytic defluoroborylation platform through direct B−H activation of N‐heterocyclic carbene boranes, through the synergistic merger of a photoredox catalyst and a hydrogen atom transfer catalyst. This atom‐economic and operationally simple protocol has enabled defluoroborylation of an extremely broad scope of multifluorinated substrates including polyfluoroarenes, gem‐difluoroalkenes, and trifluoromethylalkenes in a highly selective fashion. Intriguingly, the defluoroborylation protocol can be transition‐metal free, and the regioselectivity obtained is complementary to the reported transition‐metal‐catalysis in many cases. A practical and selective defluoroborylation of polyfluoroarenes, gem‐difluoroalkenes, and trifluoromethylalkenes was developed through photoredox and hydrogen atom transfer induced B−H activation to synthesize fluorinated organoboranes as the building blocks for value‐added organofluorine compounds.