Anhydrous Tetramethylammonium Fluoride for Room-Temperature SNAr Fluorination

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• 作者：Sydonie D. Schimler ; Sarah J. Ryan ; Douglas C. Bland ; John E. Anderson ; Melanie S. Sanford
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：December 18, 2015
• 年：2015
• 卷：80
• 期：24
• 页码：12137-12145
• 全文大小：453K
• ISSN：1520-6904

文摘

This paper describes the room-temperature S_NAr fluorination of aryl halides and nitroarenes using anhydrous tetramethylammonium fluoride (NMe₄F). This reagent effectively converts aryl-X (X = Cl, Br, I, NO₂, OTf) to aryl-F under mild conditions (often room temperature). Substrates for this reaction include electron-deficient heteroaromatics (22 examples) and arenes (5 examples). The relative rates of the reactions vary with X as well as with the structure of the substrate. However, in general, substrates bearing X = NO₂ or Br react fastest. In all cases examined, the yields of these reactions are comparable to or better than those obtained with CsF at elevated temperatures (i.e., more traditional halex fluorination conditions). The reactions also afford comparable yields on scales ranging from 100 mg to 10 g. A cost analysis is presented, which shows that fluorination with NMe₄F is generally more cost-effective than fluorination with CsF.