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Renewable Reagent for Nucleophilic Fluorination

[Image: see text] Herein, we report a study on the reactivity of three 1,3-diarylimidazolium-based fluoride reagents, with a general formula of [IPrH][F(HF)(n)] (n = 0, 1, or 2), that tackle the challenges of limited solubility, hygroscopicity, instability, and laborious preparation procedures of nu...

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Detalles Bibliográficos
Autores principales: Alič, Blaž, Petrovčič, Jan, Jelen, Jan, Tavčar, Gašper, Iskra, Jernej
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9087198/
https://www.ncbi.nlm.nih.gov/pubmed/35438994
http://dx.doi.org/10.1021/acs.joc.2c00247
Descripción
Sumario:[Image: see text] Herein, we report a study on the reactivity of three 1,3-diarylimidazolium-based fluoride reagents, with a general formula of [IPrH][F(HF)(n)] (n = 0, 1, or 2), that tackle the challenges of limited solubility, hygroscopicity, instability, and laborious preparation procedures of nucleophilic fluoride reagents. Fluorination of 4-tert-butylbenzyl bromide reveals that trifluoride [IPrH][F(HF)(2)] is the most selective reagent. Microwave-assisted activation coupled with the addition of sterically hindered amine DIPEA or alkali metal fluorides increases the rate of fluorination with [IPrH][F(HF)(2)], making it an excellent reagent for the fluorination of various organic substrates. The scope of substrates includes benzyl bromides, iodides, chlorides, aliphatic halides, tosylates, mesylates, α-haloketones, a silyl chloride, acyl and sulfuryl chlorides, and a nitroarene. The exceptional stability of the air-stable and nonhygroscopic [IPrH][F(HF)(2)] reagent is illustrated by its convenient synthesis and detailed experimental regeneration protocol using hydrofluoric acid without organic solvents.