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Kucharski MM, Watson AJB, Lloyd-Jones GC. Speciation and kinetics of fluoride transfer from tetra- n-butylammonium difluorotriphenylsilicate ('TBAT'). Chem Sci 2024; 15:4331-4340. [PMID: 38516098 PMCID: PMC10952091 DOI: 10.1039/d3sc05776c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 12/06/2023] [Indexed: 03/23/2024] Open
Abstract
Tetra-n-butylammonium difluorotriphenylsilicate (TBAT) is a conveniently handled anhydrous fluoride source, commonly used as a surrogate for tetra-n-butylammonium fluoride (TBAF). While prior studies indicate that TBAT reacts rapidly with fluoride acceptors, little is known about the mechanism(s) of fluoride transfer. We report on the interrogation of the kinetics of three processes in which fluoride is transferred from TBAT, in THF and in MeCN, using a variety of NMR methods, including chemical exchange saturation transfer, magnetisation transfer, diffusion analysis, and 1D NOESY. These studies reveal ion-pairing between the tetra-n-butylammonium and difluorotriphenylsilicate moieties, and a very low but detectable degree of fluoride dissociation, which then undergoes further equilibria and/or induces decomposition, depending on the conditions. Degenerate exchange between TBAT and fluorotriphenylsilane (FTPS) is very rapid in THF, inherently increases in rate over time, and is profoundly sensitive to the presence of water. Addition of 2,6-di-tert-butylpyridine and 3 Å molecular sieves stabilises the exchange rate, and both dissociative and direct fluoride transfer are shown to proceed in parallel under these conditions. Degenerate exchange between TBAT and 2-naphthalenyl fluorosulfate (ARSF) is not detected at the NMR timescale in THF, and is slow in MeCN. For the latter, the exchange is near-fully inhibited by exogenous FTPS, indicating a predominantly dissociative character to this exchange process. Fluorination of benzyl bromide (BzBr) with TBAT in MeCN-d3 exhibits moderate progressive autoinhibition, and the initial rate of the reaction is supressed by the presence of exogenous FTPS. Overall, TBAT can act as a genuine surrogate for TBAF, as well as a reservoir for rapidly-reversible release of traces of it, with the relative contribution of the pathways depending, inter alia, on the identity of the fluoride acceptor, the solvent, and the concentration of endogenous or exogenous FTPS.
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Affiliation(s)
- Maciej M Kucharski
- School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
| | - Allan J B Watson
- School of Chemistry, University of St Andrews North Haugh, St Andrews KY16 9ST UK
| | - Guy C Lloyd-Jones
- School of Chemistry, University of Edinburgh David Brewster Road Edinburgh EH9 3FJ UK
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2
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Knuplez T, Schneider LN, Preitschopf T, Bejaoui YKJ, Zapf L, Schopper N, Maibom KAM, Sprenger JAP, Gehrke F, Lorenzen S, Graf R, Bertermann R, Fischer I, Ignat'ev NV, Finze M. Synthesis of Partially Fluorinated Alkyl Triflates by Electrochemical Fluorination (Simons Process). Chemistry 2023; 29:e202302701. [PMID: 37615512 DOI: 10.1002/chem.202302701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 08/25/2023]
Abstract
A scalable straightforward synthesis of monofluoro- and difluoromethyl triflate CF3 SO2 OCH2 F (MH2F ) and CF3 SO2 OCHF2 (MHF2 ) through electrochemical fluorination (ECF, Simons process) of methyl triflate MH3 in anhydrous hydrogen fluoride at nickel anodes is presented. The ECF method is also feasible for the preparation of the deuterated analogues CF3 SO2 OCD2 F (MD2F ) and CF3 SO2 OCDF2 (MD2F ). Surprisingly, no H/D exchange occurs during ECF of CF3 SO2 OCD3 (MD3 ); this provides further evidence for a NiF3 /NiF4 -mediated ECF mechanism. The ECF of selected partially fluorinated ethyl triflates is described, and electrochemical fluorination of CF3 SO2 OCH2 CF3 (EH2F3 ) leads to the until now unknown chiral CF3 SO2 OCHFCF3 (EHFF3 ). The analogous fluoromethyl and fluoroethyl nonaflates are also accessible by ECF. This study contains detailed spectroscopic, structural, and thermal data on (fluoro)methyl and fluoro(ethyl) triflates.
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Affiliation(s)
- Tanja Knuplez
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Leon N Schneider
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Tobias Preitschopf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Younes K J Bejaoui
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ludwig Zapf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Nils Schopper
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Kristina A M Maibom
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jan A P Sprenger
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Franziska Gehrke
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Sabine Lorenzen
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Roland Graf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ingo Fischer
- Institut für Physikalische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Nikolai V Ignat'ev
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Consultant, Merck Life Science KGaA, 64293, Darmstadt, Germany
| | - Maik Finze
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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3
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Hu W, Pan S, Xu X, Vicic DA, Qing F. Nickel‐Mediated Trifluoromethylation of Phenol Derivatives by Aryl C−O Bond Activation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wei‐Qiang Hu
- Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Science Chinese Academy of Sciences 345 Lingling Lu Shanghai 200032 China
| | - Shen Pan
- Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Science Chinese Academy of Sciences 345 Lingling Lu Shanghai 200032 China
| | - Xiu‐Hua Xu
- Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Science Chinese Academy of Sciences 345 Lingling Lu Shanghai 200032 China
| | - David A. Vicic
- Department of Chemistry Lehigh University 6 E. Packer Avenue Bethlehem PA 18015 USA
| | - Feng‐Ling Qing
- Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Science Chinese Academy of Sciences 345 Lingling Lu Shanghai 200032 China
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4
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Hu WQ, Pan S, Xu XH, Vicic DA, Qing FL. Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C-O Bond Activation. Angew Chem Int Ed Engl 2020; 59:16076-16082. [PMID: 32452144 DOI: 10.1002/anie.202004116] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/15/2020] [Indexed: 12/18/2022]
Abstract
The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF3 ). The strategy relies on PMe3 -promoted oxidative addition and transmetalation, and CCl3 CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.
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Affiliation(s)
- Wei-Qiang Hu
- Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - Shen Pan
- Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - Xiu-Hua Xu
- Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - David A Vicic
- Department of Chemistry, Lehigh University, 6 E. Packer Avenue, Bethlehem, PA, 18015, USA
| | - Feng-Ling Qing
- Key Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
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Jana S, Telu S, Yang BY, Haskali MB, Jakobsson JE, Pike VW. Rapid Syntheses of [ 11C]Arylvinyltrifluoromethanes through Treatment of ( E)-Arylvinyl(phenyl)iodonium Tosylates with [ 11C]Trifluoromethylcopper(I). Org Lett 2020; 22:4574-4578. [PMID: 32459101 DOI: 10.1021/acs.orglett.0c01705] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a method for labeling arylvinyltrifluoromethanes with carbon-11 (t1/2 = 20.4 min) as representatives of a new radiolabeled chemotype that has potential for developing radiotracers for biomedical imaging with positron emission tomography. Treatment of (E)-arylvinyl(phenyl)iodonium tosylates (1a-1k) with [11C[CuCF3 gave the corresponding [11C]arylvinyltrifluoromethanes ([11C]2a-[11C]2k) in high radiochemical yields (90-97%) under rapid (2 min) and mild (60 °C) conditions.
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Affiliation(s)
- Susovan Jana
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive., Bethesda, Maryland 20892, United States
| | - Sanjay Telu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive., Bethesda, Maryland 20892, United States
| | - Bo Yeun Yang
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive., Bethesda, Maryland 20892, United States
| | - Mohammad B Haskali
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive., Bethesda, Maryland 20892, United States
| | - Jimmy E Jakobsson
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive., Bethesda, Maryland 20892, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive., Bethesda, Maryland 20892, United States
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6
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Polley A, Bairy G, Das P, Jana R. Triple Mode of Alkylation with Ethyl Bromodifluoroacetate:
N
, or
O
‐Difluoromethylation,
N
‐Ethylation and
S
‐(ethoxycarbonyl)difluoromethylation. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201800824] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Arghya Polley
- Organic and Medicinal Chemistry DivisionCSIR-Indian Institute of Chemical Biology 4 Raja S. C. Mullick Road, Jadavpur Kolkata- 700032, West Bengal India
- Academy of Scientific and Innovative Research (AcSIR) Kolkata- 700032 India
| | - Gurupada Bairy
- Organic and Medicinal Chemistry DivisionCSIR-Indian Institute of Chemical Biology 4 Raja S. C. Mullick Road, Jadavpur Kolkata- 700032, West Bengal India
- Academy of Scientific and Innovative Research (AcSIR) Kolkata- 700032 India
| | - Pritha Das
- Organic and Medicinal Chemistry DivisionCSIR-Indian Institute of Chemical Biology 4 Raja S. C. Mullick Road, Jadavpur Kolkata- 700032, West Bengal India
| | - Ranjan Jana
- Organic and Medicinal Chemistry DivisionCSIR-Indian Institute of Chemical Biology 4 Raja S. C. Mullick Road, Jadavpur Kolkata- 700032, West Bengal India
- Academy of Scientific and Innovative Research (AcSIR) Kolkata- 700032 India
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7
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Lin X, Li Z, Han X, Weng Z. Trifluoromethylation of (hetero)aryl iodides and bromides with copper(i) chlorodifluoroacetate complexes. RSC Adv 2016. [DOI: 10.1039/c6ra15547b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new copper-mediated trifluoromethylation of aryl halides using copper(i) chlorodifluoroacetate complexes as reagent has been developed.
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Affiliation(s)
- Xiaoxi Lin
- State Key Laboratory of Photocatalysis on Energy and Environment
- College of Chemistry
- Fuzhou University
- China
| | - Zhengyu Li
- State Key Laboratory of Photocatalysis on Energy and Environment
- College of Chemistry
- Fuzhou University
- China
| | - Xiaoyan Han
- Testing and Analysis Center
- Soochow University
- Suzhou 215123
- China
| | - Zhiqiang Weng
- State Key Laboratory of Photocatalysis on Energy and Environment
- College of Chemistry
- Fuzhou University
- China
- State Key Laboratory of Structural Chemistry
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