- Fluorination of arylboronic esters enabled by bismuth redox catalysis
-
Bismuth catalysis has traditionally relied on the Lewis acidic properties of the element in a fixed oxidation state. In this paper, we report a series of bismuth complexes that can undergo oxidative addition, reductive elimination, and transmetallation in a manner akin to transition metals. Rational ligand optimization featuring a sulfoximine moiety produced an active catalyst for the fluorination of aryl boronic esters through a bismuth (III)/bismuth (V) redox cycle. Crystallographic characterization of the different bismuth species involved, together with a mechanistic investigation of the carbonfluorine bond-forming event, identified the crucial features that were combined to implement the full catalytic cycle.
- Planas, Oriol,Wang, Feng,Leutzsch, Markus,Cornella, Josep
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p. 313 - 317
(2020/01/28)
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- Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
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An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions (25–60 °C), and features a wide substrate scope and good functional-group compatibility.
- Xing, Bo,Ni, Chuanfa,Hu, Jinbo
-
supporting information
p. 9896 - 9900
(2018/07/31)
-
- Application of trivalent iodine compounds as catalysts in Bal-Schiemann reaction
-
The invention discloses an application of trivalent iodine compounds shown in formula I and/or II in the description and used as catalysts in Bal-Schiemann reaction. The trivalent iodine compounds areused as the catalysts in the Bal-Schiemann reaction, so that the Bal-Schiemann reaction can be conducted at room temperature or near room temperature when a thermochemical method is used, and the reaction has mild reaction conditions, wide substrate use range and short reaction time, and is safe and easy to operate, products are easy to separate, and raw materials are simple and low in toxicity.
- -
-
Paragraph 0152; 0158
(2018/10/19)
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- Expanding the Balz–Schiemann Reaction: Organotrifluoroborates Serve as Competent Sources of Fluoride Ion for Fluoro-Dediazoniation
-
The Balz–Schiemann reaction endures as a method for the preparation of (hetero)aryl fluorides yet is eschewed due to the need for harsh conditions or high temperatures along with the need to isolate potentially explosive diazonium salts. In a departure from these conditions, we show that various organotrifluoroborates (RBF3?s) may serve as fluoride ion sources for solution-phase fluoro-dediazoniation in organic solvents under mild conditions. This methodology was successfully extended to a one-pot process obviating aryl diazonium salt isolation. Sterically hindered (hetero)anilines are fluorinated under unprecedentedly mild conditions in good-to-excellent yields. Taken together, this work expands the repertoire of RBF3?s to act as fluorine ion sources in an update to the classic Balz–Schiemann reaction.
- Mohy El Dine, Tharwat,Sadek, Omar,Gras, Emmanuel,Perrin, David M.
-
supporting information
p. 14933 - 14937
(2018/09/25)
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- An N-heterocyclic carbene-based nickel catalyst for the Kumada–Tamao–Corriu coupling of aryl bromides and tertiary alkyl Grignard reagents
-
In this study, nickel-catalyzed coupling reactions between arylhalides and tert-alkyl Grignard reagents were developed. Our original bicyclic NHC ligands reduced the formation of isomerized products, and we found that NMP as a co-solvent suppressed the reduction process. Under the optimal conditions we developed, the catalyst loading was lowered to 0.5?mol?%, and catalyst loading using ortho-substituted aryl bromides was also applicable at the level of 2.0?mol?%.
- Ando, Shin,Mawatari, Mai,Matsunaga, Hirofumi,Ishizuka, Tadao
-
supporting information
p. 3287 - 3290
(2016/07/11)
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- Copper-Mediated Oxidative Fluorination of Aryl Stannanes with Fluoride
-
A regiospecific method for the oxidative fluorination of aryl stannanes using tetrabutylammonium triphenyldifluorosilicate (TBAT) and copper(II) triflate is described. This reaction is robust, uses readily available reagents, and proceeds via a stepwise protocol under mild conditions (60 °C, 3.2 h). Broad functional group tolerance, including arenes containing protic and nucleophilic groups, is demonstrated.
- Gamache, Raymond F.,Waldmann, Christopher,Murphy, Jennifer M.
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supporting information
p. 4522 - 4525
(2016/09/28)
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- Synthesis of aryl fluorides from potassium aryltrifluoroborates and selectfluor mediated by iron(III) chloride
-
The synthesis of fluorinated arenes by the iron-mediated fluorination of potassium aryltrifluoroborates with Selectfluor and potassium fluoride is described. The fluorination reaction uses commercially available reagents and without requiring the addition
- Dubbaka, Srinivas Reddy,Gadde, Satyanarayana,Narreddula, Venkateswara Reddy
-
p. 854 - 860
(2015/03/14)
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- FLUORINATION OF ARYL COMPOUNDS
-
The invention provides compositions and methods of using the compositions in fluorinating aryl precursors containing a leaving group replaceable by a fluorine atom. The compositions include a metal ion source, a electrophilic fluorine source, a base, and a compound, which is an aryl precursor of the aryl fluoride, and which has a leaving group replaceable by the fluorine atom. Exemplary methods of the invention make use of such compositions and methods to prepare an aryl fluoride compound. In an exemplary embodiment, the electrophilic fluorine source is a source of 18F.
- -
-
Paragraph 00117; 00118-00121
(2014/07/22)
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- Silver-mediated fluorination of potassium aryltrifluoroborates with Selectfluor Dedicated to Professor Andrea Vasella on the occasion of his 71st birthday
-
A simple and practical procedure for the silver-mediated fluorination of aryl- and heteroaryltrifluoroborates with electrophilic fluorine from Selectfluor and LiOH·H2O is presented. The reaction procedure is simple and easy to set up, the process produces fluorinated arenes and heteroarenes in good to excellent yields and a wide range of electronically and structurally diverse substrates are tolerated.
- Dubbaka, Srinivas Reddy,Narreddula, Venkateswara Reddy,Gadde, Satyanarayana,Mathew, Thresen
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p. 9676 - 9681
(2015/01/08)
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- Cu-catalyzed fluorination of diaryliodonium salts with KF
-
A mild Cu-catalyzed nucleophilic fluorination of unsymmetrical diaryliodonium salts with KF is described. This protocol preferentially fluorinates the smaller aromatic ligand on iodine(III). The reaction exhibits a broad substrate scope and proceeds with high chemoselectivity and functional group tolerance. DFT calculations implicate a CuI/CuIII catalytic cycle.
- Ichiishi, Naoko,Canty, Allan J.,Yates, Brian F.,Sanford, Melanie S.
-
supporting information
p. 5134 - 5137
(2013/10/22)
-
- Fluorination of aryl boronic acids using acetyl hypofluorite made directly from diluted fluorine
-
Aryl boronic acids or pinacol esters containing EDG were converted in good yields and fast reactions to the corresponding aryl fluorides using the readily obtainable solutions of AcOF. In reactions with aryl boronic acids containing EWG at the para position, there are two competing forces: one directing the fluorination to take place ortho to the boronic acid and the other, toward an ipso substitution. With EWG meta to the boronic acid, substitution ipso to the boron moiety takes place in good yields.
- Vints, Inna,Gatenyo, Julia,Rozen, Shlomo
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p. 11794 - 11797
(2014/01/06)
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- Copper-mediated fluorination of arylboronate esters. Identification of a Copper(III) fluoride complex
-
A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through arylboronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III), followed by rate-limiting transmetalation of a bound arylboronate to Cu(III). Fast C-F reductive elimination is proposed to occur from an aryl-copper(III)-fluoride complex. Cu(III) intermediates have been generated independently and identified by NMR spectroscopy and ESI-MS.
- Fier, Patrick S.,Luo, Jingwei,Hartwig, John F.
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p. 2552 - 2559
(2013/03/29)
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- Palladium(III)-catalyzed fluorination of arylboronic acid derivatives
-
A practical, palladium-catalyzed synthesis of aryl fluorides from arylboronic acid derivatives is presented. The reaction is operationally simple and amenable to multigram-scale synthesis. Evaluation of the reaction mechanism suggests a single-electron-transfer pathway, involving a Pd(III) intermediate that has been isolated and characterized.
- Mazzotti, Anthony R.,Campbell, Michael G.,Tang, Pingping,Murphy, Jennifer M.,Ritter, Tobias
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p. 14012 - 14015
(2013/10/21)
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- Mild copper-mediated fluorination of aryl stannanes and aryl trifluoroborates
-
This communication describes a mild copper-mediated fluorination of aryl stannanes and aryl trifluoroborates with N-fluoro-2,4,6-trimethylpyridinium triflate. This protocol demonstrates broad substrate scope and functional group tolerance, and does not require the use of any noble metal additives. The reaction is proposed to proceed via an arylcopper(III) fluoride intermediate.
- Ye, Yingda,Sanford, Melanie S.
-
supporting information
p. 4648 - 4651
(2013/05/09)
-
- Cu(OTf)2-mediated fluorination of aryltrifluoroborates with potassium fluoride
-
This Communication describes the Cu(OTf)2-mediated fluorination of aryltrifluoroborates with KF. The reaction proceeds under mild conditions (at 60 C over 20 h) and shows a broad substrate scope and functional group tolerance. The Cu is proposed to play two separate roles in this transformation: (1) as a mediator for the aryl-F coupling and (2) as an oxidant for accessing a proposed CuIII(aryl)(F) intermediate.
- Ye, Yingda,Schimler, Sydonie D.,Hanley, Patrick S.,Sanford, Melanie S.
-
supporting information
p. 16292 - 16295
(2013/12/04)
-
- Copper-mediated fluorination of aryl iodides
-
The synthesis of aryl fluorides has been studied intensively because of the importance of aryl fluorides in pharmaceuticals, agrochemicals, and materials. The stability, reactivity, and biological properties of aryl fluorides can be distinct from those of the corresponding arenes. Methods for the synthesis of aryl fluorides, however, are limited. We report the conversion of a diverse set of aryl iodides to the corresponding aryl fluorides. This reaction occurs with a cationic copper reagent and silver fluoride. Preliminary results suggest this reaction is enabled by a facile reductive elimination from a cationic arylcopper(III) fluoride.
- Fier, Patrick S.,Hartwig, John F.
-
supporting information; experimental part
p. 10795 - 10798
(2012/08/07)
-
- Nickel-catalyzed cross-coupling of aryl bromides with tertiary grignard reagents utilizing donor-functionalized N-heterocyclic carbenes (NHCs)
-
Metal-catalyzed cross-coupling reactions are among the most important transformations in organic synthesis, allowing the efficient construction of complex structures from simpler, readily available building blocks.Many applications in large and small-scale synthesis can be found in different areas such as agrochemicals, pharmaceuticals and supramolecular chemistry. Whereas the coupling of sp2-hybridized carbon atoms in either reaction partner is well established, the use of CACHTUNGTRENUNG(sp3)-hybridized substrates presents some challenges. Catalytic cross-coupling of sterically hindered tertiary alkyl substrates is especially difficult, generally resulting in low yields, and thus, only few reports exist.[27] A big challenge in this field is not only to get the required level of reactivity, but also to overcome competing pathways like β-hydride elimination, hydrodehalogenation or isomerization
- Lohre, Claudia,Droege, Thomas,Wang, Congyang,Glorius, Frank
-
supporting information; experimental part
p. 6052 - 6055
(2011/06/25)
-
- Ipso-Fluorination of aryltrimethylsilanes using xenon difluoride
-
Reaction of aryltrimethylsilanes with xenon difluoride in C 6F6/Pyrex at room temperature gives aryl fluorides in good yield. The reaction is inhibited when acetonitrile is used as solvent but proceeds well in CFCl3/Pyrex or CH 2Cl2/Pyrex. Pyrex appears to be a very effective heterogeneous catalyst for this ipso-fluorination. The reaction does not proceed in PTFE, quartz, soda glass or glassy-carbon flasks or Pyrex flasks pre-rinsed with 2 M NaOH. Aryltrimethylstannanes and arylboronic acids and their esters do not undergo ipso-fluorination under similar conditions. Plausible mechanisms involving electrophilic addition of polarised xenon difluoride [FXeδ+?F→Pyrex δ-] followed by ligand coupling are discussed.
- Lothian, Aileen P.,Ramsden, Christopher A.,Shaw, Maxine M.,Smith, Rachel G.
-
experimental part
p. 2788 - 2793
(2011/05/02)
-
- FLUORINATION OF ORGANIC COMPOUNDS
-
Methods for fluorinating organic compounds are described herein.
- -
-
Page/Page column 91
(2010/07/10)
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- HETEROARYL COMPOUNDS USEFUL AS RAF KINASE INHIBITORS
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The present invention provides compounds of formula (I) useful as inhibitors of Raf protein kinase. The present invention also provides compositions thereof, and methods of treating Raf -mediated diseases.
- -
-
Page/Page column 163
(2010/08/04)
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- Metal-free electrophilic fluorination of alkyl trifluoroborates and boronic acids
-
Secondary alkyl trifluoroborates undergo facile electrophilic fluorination under mild conditions to afford the corresponding benzylic fluorinated adducts in excellent yield.
- Cazorla, Clément,Métay, Estelle,Andrioletti, Bruno,Lemaire, Marc
-
experimental part
p. 3936 - 3938
(2009/09/30)
-
- Non-catalytic conversion of C-F bonds of benzotrifluorides to C-C bonds using organoaluminium reagents
-
A facile method for the conversion of C-F bonds of benzotrifluorides to C-C bonds has been developed using aluminium reagents in the absence of catalysts.
- Terao, Jun,Nakamura, Misaki,Kambe, Nobuaki
-
supporting information; experimental part
p. 6011 - 6013
(2010/11/16)
-
- Carbon-carbon coupling of C(sp3)-F bonds using alumenium catalysis
-
Dialkylalumenium cation equivalents coupled with the hexabromocarborane anion function as efficient and long-lived catalysts for alkylation of aliphatic C-F bonds (alkylative defluorination or AlkDF) by alkylaluminum compounds. Only C(sp3)-F bo
- Gu, Weixing,Haneline, Mason R.,Douvris, Christos,Ozerov, Oleg V.
-
experimental part
p. 11203 - 11212
(2009/12/05)
-
- SYSTEM FOR FLUORINATING ORGANIC COMPOUNDS
-
Described herein are fluorinated organic compounds and methods of making fluorinated organic compounds, for example, using palladium complexes. Also described herein are compositions and kits containing compounds and palladium complexes described herein.
- -
-
Page/Page column 232; 240
(2009/10/09)
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- Fluorination of boronic acids mediated by silver(I) Triflate
-
A regiospecific Ag-mediated fluorination reaction of aryl- and alkenylboronic acids and esters Is reported. The fluorination reaction uses commercially available reagents, does not require the addition of exogenous ligands, and can be performed on a multigram scale. This report discloses the first practical reaction sequence from arylboronic acid to aryl fluorides.
- Furuya, Takeru,Ritter, Toblas
-
supporting information; experimental part
p. 2860 - 2863
(2009/12/05)
-
- Palladium-mediated fluorination of arylboronic acids
-
(Chemical Equation Presented) Saving the best for last: Novel palladium complexes allow mild, two-step fluorination of aryl boronic acids (see scheme). The reaction is regiospecific, functional-group tolerant, has a broad substrate scope, and is ideally suited for the introduction of fluorine substituents at a late stage for aryl fluoride synthesis.
- Furuya, Takeru,Kaiser, Hanns Martin,Ritter, Tobias
-
supporting information; experimental part
p. 5993 - 5996
(2009/03/11)
-
- Carbon-fluorine reductive elimination from a high-valent palladium fluoride
-
We have observed two high-valent arylpalladiumfluoride complexes that afford carbon-fluorine bond formation upon thermolysis. Copyright
- Furuya, Takeru,Ritter, Tobias
-
supporting information; experimental part
p. 10060 - 10061
(2009/02/03)
-
- Halo- and azidodediazoniation of arenediazonium tetrafluoroborates with trimethylsilyl halides and trimethylsilyl azide and Sandmeyer-type bromodediazoniation with Cu(I)Br in [BMIM][PF6] ionic liquid
-
(Chemical Equation Presented) Reaction of [ArN2][BF4] salts immobilized in [BMIM][PF6] ionic liquid (IL) with TMSX (X = I, Br) and TMSN3 represents an efficient method for the preparation of iodo-, bromo-, and azido-derivatives via dediazoniation. The reactions can also be effected starting with ArNH2 by in situ diazotization with [NO][BF4] followed by reaction with TMSX or TMSN3. Depending on the substituents on the benzenediazonium cation, competing fluorodediazoniation (ArF formation) and hydrodediazoniation (ArH formation) were observed. Dediazoniation with TMSN3 and with TMSI generally gave the highest chemoselectivity toward ArN3 and ArI formation. The IL was recycled and reused up to 5 times with no appreciable decrease in the conversions. Multinuclear NMR monitoring of the interaction of [ArN 2][BF4]/TMSX, [BMIM][PF6]/TMSX, and [BMIM][PF6]/TMSX/[ArN2][BF4] indicated that TMSF is formed primarily via [ArN2][BF4]/ TMSX, generating [ArN2][X] in situ, which gives ArX on dediazoniation. Competing formation of ArF in Sandmeyer-type bromodediazoniation of [ArN 2][BF4] with Cu(I)Br immobilized in the IL points to significant involvement of heterolytic dediazoniation.
- Hubbard, Abigail,Okazaki, Takao,Laali, Kenneth K.
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p. 316 - 319
(2008/09/17)
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- N-(trifluoromethylsulfonyl)aryloxytrifluoromethylsulfoximines [ArO-SO(CF3)=NTf] and N-aryltriflimides Ar-N(Tf)2 by thermal and photolytic dediazoniation of [ArN2][BF4] in [BMIM][Tf2N] ionic liquid: Exploiting the ambident nucleophilic character of a "nonnucleophilic" anion
-
(Chemical Equation Presented) Arenediazonium tetrafluoroborate salts undergo metathesis on immobilization in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonato)amide [BMIM][Tf2N]. The "noncoordinating", "nonnucleophilic" [Tf2N] anion acts as an ambident nucleophile toward the aryl cations, formed via thermal dediazoniation, to give predominantly the oxy anion quenching products [ArO-SO(CF3)=NTf], with minimal formation of ArN(Tf)2, irrespective of the nature of the substituent(s) on the ArN2 +. Strong preference for the formation of oxygen trapping products did not change under photolytic conditions, where dediazoniation occurs at room temperature. A minimal amount of the Schiemann product ArF is also formed in both thermal and photolytic dediazoniation, depending on the substituent(s). Progress of dediazoniation in the IL (both thermal and photolytic) and the evolution of the products were directly monitored by 1H and 19F NMR. According to DFT (Density Functional Theory) calculations, PhN(Tf)2 is more stable than PhO-SO(CF3)=NTf by 15-17 kcal/mol, depending on the basis set. Inclusion of solvation effects (PCM, with acetone and with CH2ClCH2Cl as solvent) did not change this preference. The [ArN2][BF4] dediazoniation in [BMIM][Tf2N] resulted in synthesis and characterization of a series of hitherto unknown [ArO-SO(CF3)=NTf] compounds. The X-ray structure of MesO-SO(CF3)=NTf (Mes = mesityl) is reported. On the basis of extraction studies, suitable solvent systems have been identified that remove the products without dissolving [BMIM][NTf2], thus overcoming product recovery difficulties typically associated with the use of this IL.
- Laali, Kenneth K.,Okazaki, Takao,Bunge, Scott D.
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p. 6758 - 6762
(2008/02/10)
-
- (Sensitized) photolysis of diazonium salts as a mild general method for the generation of aryl cations. Chemoselectivity of the singlet and triplet 4-substituted phenyl cations
-
(Chemical Equation Presented) The photolysis of a series of 4-X-benzenediazonium tetrafluoroborates is studied in MeCN. Loss of nitrogen occurs from the singlet excited state with X = H, t-Bu, and NMe2 and leads to the singlet aryl cation. This adds to the solvent yielding the corresponding acetanilides. With other substituents, ISC competes with (X = Br, CN) or overcomes (X = COMe, NO2) fragmentation and the aryl cation is formed in part or completely in the triplet state. In neat MeCN, this either abstracts hydrogen from the solvent (in most cases inefficiently) or undergoes intersystem crossing to the more stable singlet that reacts as above. In the presence of π nucleophiles (allyltrimethylsilane or benzene), the triplet aryl cation is efficiently trapped giving substituted allylbenzenes and biphenyls, respectively. By triplet sensitization by xanthone, the triplet cation and the products from it are obtained from the whole series considered. The direct or sensitized photodecomposition of diazonium fluoroborates, substituted with both electron-donating and -withdrawing substituents, in the presence of alkenes and arenes offers an access to an alternative arylation procedure.
- Milanesi, Silvia,Fagnoni, Maurizio,Albini, Angeld
-
p. 603 - 610
(2007/10/03)
-
- Fluorodediazoniation in ionic liquid solvents: New life for the Balz-Schiemann reaction
-
Drawbacks associated with the classic Balz-Schiemann reaction are eliminated in a series of examples by conducting fluorodediazoniation in ionic liquid solvents, thus opening up a new horizon for a much in demand process.
- Laali, Kenneth K.,Gettwert, Volker J.
-
-
- The synthesis of [18F]fluoroarenes from the reaction of cyclotron-produced [18F]fluoride ion with diaryliodonium salts
-
Diaryliodonium salts have been shown to react with fluoride ion at 80°C in acetonitrile to generate aryl fluorides. The regioselectivity is controlled electronically and by the bulk of the ortho-substituents on the rings, with the latter the dominant factor such that electron-rich rings can be fluorinated. ortho-Substituted aryl fluorides can be selectively produced from unsymmetrical diaryliodonium salts. The process has been used to synthesise [18F] labelled aromatics by the use of cyclotron generated [18F]fluoride ion.
- Shah, Aneela,Pike, Victor W.,Widdowson, David A.
-
p. 2043 - 2046
(2007/10/03)
-
- THE CONFORMATIONAL DEPENDENCE OF 6jPF,C IN SOME 4-FLUOROPHENYL DERIVATIVES OF METHANE, ETHENE, AND CYCLOHEXANE
-
The spin-spin coupling over six bonds between (19)F and (13)C nuclei on the sidechain in thirteen 4-fluorophenyl derivatives appears to be mediated by a ?-? mechanism.Its magnitude depends somewhat on the hybridization state of the carbon atom carrying th
- Schaefer, Ted,Peeling, James,Glenn, H. Penner,Lemire, Alberta,Sebastian, Rudy
-
-
- Complexation of Arenediazonium Ions by Macrocyclic Multidentate Compounds
-
A kinetic technique is utilized to determine the relative complexing abilities of 40 macrocyclic multidentate compounds for p-tert-butylbenzenediazonium tetrafluoroborate in 1,2-dichloroethane.The influence of ligand structure variations, such as ring size, nature of heteroatoms, and substituent effects, upon complexation efficiency is assessed.Maximum complexation is achieved with a 21-membered polyether macrocycle.
- Bartsch, Richard A.,Juri, Pedro N.
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p. 1011 - 1014
(2007/10/02)
-