- Anhydrous Tetramethylammonium Fluoride for Room-Temperature SNAr Fluorination
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This paper describes the room-temperature SNAr 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.
- Schimler, Sydonie D.,Ryan, Sarah J.,Bland, Douglas C.,Anderson, John E.,Sanford, Melanie S.
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- METHOD FOR AROMATIC FLUORINATION
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Disclosed is a f fluorination method comprising providing a fluorinating reagent and a solvent to a reaction mixture; providing a compound having the formula Ar-X to the reaction mixture; wherein, A is a aryl, substituted aryl, heteroaryl or substituted heteroaryl, and X is CI, Br, I or NO2, providing tetramethylammonium 2,6-dimethylphenolate to the reaction mixture; and reacting under conditions sufficient to provide a species having the formula Ar-F.
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Paragraph 0033-0035; 0044
(2018/03/25)
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- Multiple Approaches to the in Situ Generation of Anhydrous Tetraalkylammonium Fluoride Salts for SNAr Fluorination Reactions
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This article focuses on the development of practical approaches to the in situ generation of anhydrous fluoride salts for applications in nucleophilic aromatic substitution (SNAr) reactions. We report herein that a variety of combinations of inexpensive nucleophiles (e.g., tetraalkylammonium cyanide and phenoxide salts) and fluorine-containing electrophiles (e.g., acid fluoride, fluoroformate, benzenesulfonyl fluoride, and aryl fluorosulfonate derivatives) are effective for this transformation. Ultimately, we demonstrate that the combination of tetramethylammonium 2,6-dimethylphenoxide and sulfuryl fluoride (SO2F2) serves as a particularly practical route to anhydrous tetramethylammonium fluoride. This procedure is applied to the SNAr fluorination of a range of electron-deficient aryl and heteroaryl chlorides as well as nitroarenes.
- Cismesia, Megan A.,Ryan, Sarah J.,Bland, Douglas C.,Sanford, Melanie S.
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p. 5020 - 5026
(2017/05/24)
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- PROCESS FOR FLUORINATING COMPOUNDS
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Disclosed are mild temperature (e.g., from 0 to 80°C) SNAr fluorinations of a variety of halide and sulfonate substituted aryl and heteroaryl substrates using NMe4F.
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Page/Page column 20-21; 29
(2017/02/28)
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- Nucleophilic deoxyfluorination of phenols via aryl fluorosulfonate intermediates
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This report describes a method for the deoxyfluorination of phenols with sulfuryl fluoride (SO2F2) and tetramethylammonium fluoride (NMe4F) via aryl fluorosulfonate (ArOFs) intermediates. We first demonstrate that the reaction of ArOFs with NMe4F proceeds under mild conditions (often at room temperature) to afford a broad range of electronically diverse and functional group-rich aryl fluoride products. This transformation was then translated to a one-pot conversion of phenols to aryl fluorides using the combination of SO2F2 and NMe4F. Ab initio calculations suggest that carbon-fluorine bond formation proceeds via a concerted transition state rather than a discrete Meisenheimer intermediate.
- Schimler, Sydonie D.,Cismesia, Megan A.,Hanley, Patrick S.,Froese, Robert D.J.,Jansma, Matthew J.,Bland, Douglas C.,Sanford, Melanie S.
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p. 1452 - 1455
(2017/02/10)
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- PROCESS FOR FLUORINATING COMPOUNDS
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Methods of preparing a fluorinated substrate by combining potassium fluoride, a quaternary ammonium salt, and a substrate substituted with at least one chloro, bromo, sulfonyl, or nitro group to thereby provide the fluorinated substrate are disclosed.
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- PROCESS FOR FLUORINATING COMPOUNDS
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Methods of preparing a fluorinated aryl or heteroaryl substrate by combining a quaternary ammonium cyanide and an aryl or heteroaryl substrate substituted with at least one chloro, bromo, sulfonyl, or nitro group to thereby provide a mixture, and combining the mixture with hexafluorobenzene to thereby provide the fluorinated substrate.
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Paragraph 0087-0089
(2015/05/26)
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- Acyl azolium fluorides for room temperature nucleophilic aromatic fluorination of chloro- and nitroarenes
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The reaction of acid fluorides with N-heterocyclic carbenes (NHCs) produces anhydrous acyl azolium fluorides. With appropriate selection of acid fluoride and NHC, these salts can be used for the room temperature SNAr fluorination of a variety of aryl chlorides and nitroarenes.
- Ryan, Sarah J.,Schimler, Sydonie D.,Bland, Douglas C.,Sanford, Melanie S.
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supporting information
p. 1866 - 1869
(2015/04/27)
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- PROCESS FOR FLUORINATING COMPOUNDS
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Methods of preparing a fluorinated substrate by combining potassium fluoride, imidazolium salt, and a substrate substituted with at least one chloro, bromo, sulfonyl, or nitro group to thereby provide the fluorinated substrate are disclosed.
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Paragraph 0091; 0092; 0093; 0094
(2015/05/26)
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- Developing efficient nucleophilic fluorination methods and application to substituted picolinate esters
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This report describes nucleophilic fluorination of 3 and 5-substituted picolinate ester substrates using potassium fluoride in combination with additive promoters. Agents such as tributylmethylammonium or tetraphenylphosphonium chloride were among the bes
- Allen, Laura J.,Lee, Shin Hee,Cheng, Yang,Hanley, Patrick S.,Muhuhi, Joseck M.,Kane, Elisabeth,Powers, Stacey L.,Anderson, John E.,Bell, Bruce M.,Roth, Gary A.,Sanford, Melanie S.,Bland, Douglas C.
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p. 1045 - 1054
(2014/10/15)
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- Mild fluorination of chloropyridines with in situ generated anhydrous tetrabutylammonium fluoride
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This paper describes the fluorination of nitrogen heterocycles using anhydrous NBu4F. Quinoline derivatives as well as a number of 3- and 5-substituted pyridines undergo high-yielding fluorination at room temperature using this reagent. These results with anhydrous NBu4F compare favorably to traditional halex fluorinations using alkali metal fluorides, which generally require temperatures of ≥100 °C.
- Allen, Laura J.,Muhuhi, Joseck M.,Bland, Douglas C.,Merzel, Rachel,Sanford, Melanie S.
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p. 5827 - 5833
(2014/07/08)
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