Transition‐Metal‐Free Catalytic Hydrodefluorination of Polyfluoroarenes by Concerted Nucleophilic Aromatic Substitution with a Hydrosilicate

• Published in: Angewandte Chemie International Edition Vol. 56; no. 51; pp. 16191 - 16196
• Main Authors: Kikushima, Kotaro, Grellier, Mary, Ohashi, Masato, Ogoshi, Sensuke
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 18-12-2017; Wiley-VCH Verlag
• Edition: International ed. in English
• Subjects: Catalysis; Chemical Sciences; Coordination chemistry; defluorination; Fluorides; fluoroarenes; hydride transfer; Metals; nucleophilic aromatic substitution; Salts; silicates; Substitution reactions; fluoroarenes; silicates; nucleophilic aromatic substitution; defluorination; hydride transfer
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201708003

A transition‐metal‐free catalytic hydrodefluorination (HDF) reaction of polyfluoroarenes is described. The reaction involves direct hydride transfer from a hydrosilicate as the key intermediate, which is generated from a hydrosilane and a fluoride salt. The eliminated fluoride regenerates the hydrosilicate to complete the catalytic cycle. Dispersion‐corrected DFT calculations indicated that the HDF reaction proceeds through a concerted nucleophilic aromatic substitution (CSNAr) process.
A simple but artful combination: Transition‐metal‐free catalytic hydrodefluorination (HDF) of polyfluoroarenes was enabled by a hydrosilicate catalyst formed in situ from a hydrosilane and a fluoride ion. The reaction involves direct hydride transfer from the hydrosilicate through concerted nucleophilic aromatic substitution (CSNAr; see scheme).