459-51-8Relevant academic research and scientific papers
METHOD AND REAGENT FOR DEOXYFLUORINATION
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Paragraph 0148-0150; 0152; 0163, (2021/05/29)
A safe, simple, and selective method and reagent for deoxyfluorination is disclosed. With the method and reagent disclosed herein, organic compounds such as carboxylic acids, carboxylates, carboxylic acid anhydrides, aldehydes, and alcohols can be fluorinated by using the most common nucleophilic fluorinating reagents and electron deficient fluoroarenes as mediators under mild conditions, giving corresponding fluoroorganic compounds in excellent yield with a wide range of functional group compatibility and easy product purification. For example, directly utilizing KF for deoxyfluorination of carboxylic acids provides the most economical and the safest pathway to access acyl fluorides, key intermediates for syntheses of peptide, amide, ester, and dry fluoride salts.
Nucleophilic (Radio)Fluorination of Redox-Active Esters via Radical-Polar Crossover Enabled by Photoredox Catalysis
Webb, Eric W.,Park, John B.,Cole, Erin L.,Donnelly, David J.,Bonacorsi, Samuel J.,Ewing, William R.,Doyle, Abigail G.
supporting information, p. 9493 - 9500 (2020/05/18)
We report a redox-neutral method for nucleophilic fluorination of N-hydroxyphthalimide esters using an Ir photocatalyst under visible light irradiation. The method provides access to a broad range of aliphatic fluorides, including primary, secondary, and tertiary benzylic fluorides as well as unactivated tertiary fluorides, that are typically inaccessible by nucleophilic fluorination due to competing elimination. In addition, we show that the decarboxylative fluorination conditions are readily adapted to radiofluorination with [18F]KF. We propose that the reactions proceed by two electron transfers between the Ir catalyst and redox-active ester substrate to afford a carbocation intermediate that undergoes subsequent trapping by fluoride. Examples of trapping with O- and C-centered nucleophiles and deoxyfluorination via N-hydroxyphthalimidoyl oxalates are also presented, suggesting that this approach may offer a general blueprint for affecting redox-neutral SN1 substitutions under mild conditions.
Quaternary Ammonium Trifluoromethoxide Salts as Stable Sources of Nucleophilic OCF3
Britton, Robert,Friesen, Chadron M.,Jelier, Benson J.,Martin, Rainer E.,Meanwell, Michael,Newton, Josiah J.
supporting information, p. 1785 - 1790 (2020/03/24)
The reaction of nucleophilic tertiary amines with trifluoromethyl and pentafluoroethyl methyl ethers provides quaternary ammonium trifluoromethoxide (NR4OCF3) and pentafluoroethoxide (NR4OCF2CF3) salts, respectively, in good yields. The new trifluoromethoxide salts disclosed herein are uniquely stable for extended periods of time in both the solid state and in solution, which complements contemporary reagents. Here we describe the preparation of a range of NR4OCF3 salts, their long-term stability, and utility in substitution reactions.
9-Borabicyclo[3.3.l]nonane-induced Friedel-Crafts benzylation of arenes with benzyl fluorides
Guo, Jing,Bamford, Karlee L.,Stephan, Douglas W.
supporting information, p. 5258 - 5261 (2019/06/07)
Friedel-Crafts benzylation of arenes with benzyl fluorides using 9-borabicyclo[3.3.l]nonane (9-BBN) as a mediator has been developed. This provides a simple and cheap route to the activation of C-F bonds to synthesize 1,1-diarylmethanes in good to excellent yields (up to 98%) under mild conditions. Functional group tolerance and the mechanism are considered.
Solvent free nucleophilic introduction of fluorine with [bmim][F]
Bouvet, Sébastien,Pégot, Bruce,Marrot, Jérome,Magnier, Emmanuel
, p. 826 - 829 (2014/02/14)
1-n-Butyl-3-methylimidazolium fluoride ([bmim][F]) proved very efficient fluorinated reagent for nucleophilic substitution over sulfonate esters and alkyl halides. Preparation of the ionic liquid as well as its use as the reagent has been performed to be the more eco-friendly as possible. No organic solvent is needed for the fluoride introduction, reaction times are reduced by using microwave as the heating source, and the ionic liquids carefully recycled. Furthermore, no special care has to be taken as the presence of water in [bmim][F] was not deleterious to the transformation yield.
Competitive fluorination on methyl-group and benzene-ring during the anodic fluorination of fluorotoluenes in Et4NF · mHF
Momota, Kunitaka,Yonezawa, Tetsuo,Mukai, Katsuji,Morita, Masayuki
, p. 173 - 178 (2007/10/03)
Electrochemical fluorinations of 2-fluorotoluene (2a), 3-fluorotoluene (3a) and 4-fluorotoluene (4a) in neat Et4NF · mHF (Et = C2H5, m = 3.5 or 4.0) were carried out on a platinum anode. The fluorination of 2a, 3a and 4a occurred competitively both on the side-chain (formation of monofluoromethylfluorobenzenes) and on the benzene-ring (formation of methyltrifluoro-1,4-cyclohexadienes). These results are explained by the facility of proton elimination from the methyl groups of the radical cations which have been formed by the anodic one-electron transfer reactions of 2a, 3a and 4a. A cyclic voltammogram of 4a showed three anodic current peaks which correspond to the oxidation of 4a, 1-fluoromethyl-4-fluorobenzene (4b) and 1-difluoromethyl-4-fluorolbenzene (4c). On the other hand, voltammograms of 2a and 3a showed two anodic current peaks and no difluoromethylfluorobenzenes was obtained during the fluorination of 2a and 3a.
