- Synthesis and Lewis acidity of fluorophosphonium cations
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A series of fluorophosphonium salts, [R3PF][X] (R = alkyl or aryl; X = FB(C6F5)3, [B(C6F5)4]), have been prepared by reactions of phosphine/borane frustrated Lewis pairs (FLPs) with XeF2 or difluorophosphoranes with [Et3Si][B(C6F5)4]. As the substituents bound to phosphorus become increasingly electron withdrawing, the corresponding fluorophosphonium salts are shown to be increasingly Lewis acidic. Calculations were also performed to determine the relative fluoride ion affinities (FIA) of these fluorophosphonium cations.
- Caputo, Christopher B.,Winkelhaus, Daniel,Dobrovetsky, Roman,Hounjet, Lindsay J.,Stephan, Douglas W.
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Read Online
- Examining Trichloroisocyanuric Acid and Oxalyl Chloride in Complementary Approaches to Fluorination of Group 15 Heteroatoms
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A mild, oxidative fluorination approach to a variety of fluorinated phosphorus compounds using trichloroisocyanuric acid (TCICA) and KF was developed as a complement to a recent study on deoxygenative fluorination using oxalyl chloride. Herein, the syntheses of several fluorinated organophosphorus compounds are reported, and both TCICA/KF and oxalyl chloride/KF conditions are compared and contrasted throughout. Initial investigations of the method on other group 15 heteroatoms (i. e., As, Sb, and Bi) are also reported, with varied success. This work notably extends the known TCICA/KF reactivity series to another group of elements beyond previously studied chalcogens (S, Se, and Te) and halogens (iodine) and expands the utility of the previously reported oxalyl chloride/KF method.
- Bornemann, Dustin,Brüning, Fabian,Bartalucci, Niccolò,Wettstein, Lionel,Pitts, Cody Ross
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- Synthesis of Glycosyl Fluorides by Photochemical Fluorination with Sulfur(VI) Hexafluoride
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This study describes a new convenient method for the photocatalytic generation of glycosyl fluorides using sulfur(VI) hexafluoride as an inexpensive and safe fluorinating agent and 4,4′-dimethoxybenzophenone as a readily available organic photocatalyst. This mild method was employed to generate 16 different glycosyl fluorides, including the substrates with acid and base labile functionalities, in yields of 43%-97%, and it was applied in continuous flow to accomplish fluorination on an 7.7 g scale and 93% yield.
- Bannykh, Anton,Khomutnyk, Yaroslav,Kim, Sungjin,Nagorny, Pavel
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supporting information
p. 190 - 194
(2021/01/13)
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- Cobalt-Catalyzed Divergent Aminofluorination and Diamination of Styrenes with N-Fluorosulfonamides
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A cobalt-catalyzed aminofluorination reaction of styrenes with N-fluorosulfonamides serving as both the amination and fluorination agents has been developed. The switch of selectivity in this catalytic reaction from aminofluorination to diamination could be easily achieved by the addition of 1.0 equiv of PPh3. Both transformations tolerated a wide array of substrates under mild reaction conditions.
- Guo, Peng,Han, Jun-Fa,Yuan, Guo-Cai,Chen, Lin,Liao, Jia-Bin,Ye, Ke-Yin
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supporting information
p. 4067 - 4071
(2021/05/26)
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- Fast Hydrocarbon Oxidation by a High-Valent Nickel–Fluoride Complex
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In the search for highly reactive oxidants we have identified high-valent metal–fluorides as a potential potent oxidant. The high-valent Ni–F complex [NiIII(F)(L)] (2, L=N,N′-(2,6-dimethylphenyl)-2,6-pyridinedicarboxamidate) was prepared from [NiII(F)(L)]? (1) by oxidation with selectfluor. Complexes 1 and 2 were characterized by using 1H/19F NMR, UV-vis, and EPR spectroscopies, mass spectrometry, and X-ray crystallography. Complex 2 was found to be a highly reactive oxidant in the oxidation of hydrocarbons. Kinetic data and products analysis demonstrate a hydrogen atom transfer mechanism of oxidation. The rate constant determined for the oxidation of 9,10-dihydroanthracene (k2=29 m?1 s?1) compared favorably with the most reactive high-valent metallo-oxidants. Complex 2 displayed reaction rates 2000–4500-fold enhanced with respect to [NiIII(Cl)(L)] and also displayed high kinetic isotope effect values. Oxidative hydrocarbon and phosphine fluorination was achieved. Our results provide an interesting direction in designing catalysts for hydrocarbon oxidation and fluorination.
- Lovisari, Marta,McDonald, Aidan R.,Mondal, Prasenjit,Twamley, Brendan
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supporting information
p. 13044 - 13050
(2020/06/05)
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- Direct Access to Acyl Fluorides from Carboxylic Acids Using a Phosphine/Fluoride Deoxyfluorination Reagent System
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A fast and simple method for deoxyfluorination of carboxylic acids is presented. The protocol employs commodity chemicals (PPh3, NBS, fluoride), affording products in excellent yields under mild conditions. Acyloxyphosphonium ion, the key reaction intermediate, was identified by NMR spectroscopic methods. Br?nsted acidic conditions are essential for efficient C-F bond formation. The protocol displays scalability, high functional group tolerance, chemoselectivity, and easy purification of products. Deoxyfluorination of active pharmaceutical ingredients was established.
- Munoz, Socrates B.,Dang, Huong,Ispizua-Rodriguez, Xanath,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
(2019/03/19)
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- Hypervalent Iodine-Based Activation of Triphenylphosphine for the Functionalization of Alcohols
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The use of hypervalent iodine reagents as a general tool for the activation of PPh 3 and its application to the functionalization of alcohols is reported. Combination of PPh 3 with PhICl 2 or TolIF 2 gives dihalophosphoranes that are characterized by 31 P NMR, however, with PhIOAc 2, PhI(OTFA) 2, or the cyclic chloro(benzoyloxy)iodane, no phosphoranes were observed. Reaction of these iodanes with PPh 3 in the presence of primary, secondary, or tertiary alcohols results in either halogenation or acyl-transfer products in moderate to high yield.
- Eljo, Jasmin,Carle, Myriam S.,Murphy, Graham K.
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p. 2871 - 2875
(2017/10/06)
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- Difluorotriorganylphosphoranes for the Synthesis of Fluorophosphonium and Bismuthonium Salts
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Fluoride ion affinities (FIA), provided by DFT calculations, are exceedingly useful for the design of new Lewis acids with defined reactivities. Herein, we report the synthesis, characterization and reactivity of new difluoro(perfluoroorganyl)phosphoranes, which readily abstract fluoride ions from difluoro(triorganyl)phosphoranes. Highly reactive fluorobismuthonium cations and the [Ph3Bi(NCCH3)2]2+cation are accessible through the treatment of difluoro(triorganyl)bismuth(V) compounds with the Lewis acidic phosphoranes discussed here.
- Solyntjes, Sven,Neumann, Beate,Stammler, Hans-Georg,Ignat'ev, Nikolai,Hoge, Berthold
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p. 3999 - 4010
(2016/09/13)
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- Phosphonium betaines derived from hexafluoro-1,4-naphthoquinone: Synthesis and cytotoxic and antioxidant activities
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Fluorinated derivatives of 1,4-naphthoquinones are highly potent inhibitors of Cdc25A and Cdc25B phosphatases; they suppress the growth of tumor cells. Four derivatives of phosphonium betaines derived from hexafluoro-1,4-naphthoquinone: (triphenyl[5,6,7,8-tetrafluoro-1-oxido-4-oxo-3-(phenylimino)-3,4-dihydronaphthalen-2-yl]phosphonium) (4), ((3,5-difluorophenyl)(methyl)phenyl(5,6,7,8-tetrafluoro-3-oxido-1,4-dioxo-1,4-dihydronaphthalen-2-yl)phosphonium) (5), ((2,5-difluorophenyl)(methyl)phenyl(5,6,7,8-tetrafluoro-3-oxido-1,4-dioxo-1,4-dihydronaphthalen-2-yl)phosphonium) (6) and ((3,5-difluorophenyl)diphenyl(5,6,7,8-tetrafluoro-3-oxido-1,4-dioxo-1,4-dihydronaphthalen-2-yl)phosphonium) (7) were synthesized for the first time. Their cytotoxicity toward human mammary adenocarcinoma, human myeloma, hamster and murine and fibroblasts as well as their antioxidant and mutagenic effects on a Salmonella tester strain were analyzed. All four substances showed comparable IC50values in terms of suppression of tumor cell growth, which were from two- to ninefold lower comparing with those of fibroblasts. To identify the features of spatial orientation and noncovalent interactions of the new phosphonium betaines in the binding site of Cdc25B, a molecular docking analysis was carried out. It showed that the interactions of the analyzed compounds with a Cdc25B model binding site are characterized by the presence of a large number of acceptors (fluorine and oxygen atoms, forming halogen and hydrogen bonds) and by participation of pi-systems and phosphorus in specific electrostatic interactions that may result in inhibition of enzymes of the Cdc25 family. In addition, compounds 5 and 6 (especially the latter) were found to be effective antioxidants protecting bacterial cells from H2O2-induced and spontaneous and mutagenesis at significantly lower concentrations (IC50?=?0.09 to 1.8?μM) than those of derivatives 4 and 7 (86–92?μM). Taking into account these data (together with the good cytotoxic effect on cancer cells comparing with normal mammalian cells) we can propose compounds 5 and 6 as possible useful inhibitors of tumor cell growth and antioxidants.
- Zhivetyeva, Svetlana I.,Zakharova, Olga D.,Ovchinnikova, Ludmila P.,Baev, Dmitry S.,Bagryanskaya, Irina Yu.,Shteingarts, Vitalij D.,Tolstikova, Tatiana G.,Nevinsky, Georgy A.,Tretyakov, Evgeny V.
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- A T-shaped Ni[κ2-(CF2)4-] NHC complex: Unusual Csp3-F and M-CF bond functionalization reactions
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A T-shaped octafluoronickelacyclopentane-NHC complex is prepared and characterized. While the solid-state structure includes a weak isopropyl-CH3 agostic interaction, the reactivity of this complex with Lewis- and Bronsted acids is clearly enhanced by its low coordination number. Reaction with Me3SiOTf, for example, yielded a rare metal-heptafluorocyclobutyl complex whereas carboxylic acids gave substitution at the α-carbon and/or Ni-CF bond protonolysis to afford thermally robust 4H-octafluorobutyl Ni complexes.
- Andrella, Nicholas O.,Sicard, Alexandre J.,Gorelsky, Serge I.,Korobkov, Ilia,Baker, R. Tom
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p. 6392 - 6397
(2015/10/28)
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- The use of methyl 2,2-difluoro-2-(fluorosulfonyl)acetate as the difluorocarbene source to generate an in situ source of difluoromethylene triphenylphosphonium ylide
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Under moderate conditions in the presence of a demethylating reagent, such as iodide, methyl 2,2,-difluoro-2-(fluorosulfonyl)acetate (MDFA) releases difluorocarbene, which in the presence of triphenylphosphine forms difluoromethylene triphenylphosphonium ylide. When the process is carried out also in the presence of aldehydes or activated ketones, the ensuing in situ Wittig-type reaction of the ylide with the carbonyl reactants produces 1,1-difluoroalkenes in good yield. Density Functional Theory calculations were used to provide new estimates of the energies and structures of singlet and triplet states of CH2:, CHF:, and CF2: carbenes, as well as those of their respective triphenylphosphonium ylides.
- Thomoson, Charles S.,Martinez, Henry,Dolbier Jr., William R.
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- Electrochemical fluorination using alkali-metal fluorides
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Charged up: The selective electrochemical fluorination of organic compounds using the alkali-metal fluoride KF under very mild reaction conditions has been accomplished (see scheme). The long-standing problems of low solubility of metal fluorides in organic solvent and low nucleophilicity of fluoride ions for fluorination have been overcome by the use of of poly(ethylene glycol). Copyright
- Sawamura, Takahiro,Takahashi, Kohta,Inagi, Shinsuke,Fuchigami, Toshio
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supporting information; experimental part
p. 4413 - 4416
(2012/06/18)
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- Interaction of α,α-difluoroazides with trivalent phosphorus compounds and triphenylantimony
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α,α-Difluoroazides react with triphenylantimony and various compounds of trivalent phosphorus according to the oxidative fluorination scheme. In the case of trivalent phosphorus compound the primary products are phosphazenes, phosphazides or difluorophosphoranes that may undergo further transformations to the corresponding fluorine derivatives of pentavalent phosphorus. Pleiades Publishing, Ltd., 2010.
- Lermontov,Polivanova,Shkavrov
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experimental part
p. 1646 - 1651
(2011/02/18)
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- Rhodium-catalyzed substitution reaction of aryl fluorides with disulfides: P-orientation in the polyarylthiolation of polyfluorobenzenes
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In the presence of a catalytic amount of RhH(PPh3)4 and 1,2-bis(diphenylphosphino)benzene, an aromatic fluoride, an organic disulfide (0.5 equiv), and triphenylphosphine (0.5 equiv) reacted in refluxing chlorobenzene to give an aryl sulfide in high yield. Since triphenylphosphine trapped fluoride atoms forming phosphine difluoride, both organothio groups of the disulfide reacted effectively, and the fluoride substituent reacted more readily than the chloride and bromide. The reaction of hexafluorobenzene and a diaryl disulfide gave 1,4-diarylthio-2,3,5,6-tetrafluorobenzene, 1,2,4,5-tetraarylthio-3,6-difluorobenzene, and hexaarylthiobenzene in a stepwise manner; pentafluorobenzene gave 1-arylthio-2,3,5,6-tetrafluorobenzene; 1,2,3,4-tetrafluorobenzene gave 1,2-diarylthio-3,6-difluorobenzene; and 1,2,4,5-tetrafluorobenzene gave 1,4-diarylthio-2-5-difluorobenzene. The polyarylthiolation reaction of polyfluorobenzenes exhibited a strong tendency to form 1,4-difluorobenzenes. Copyright
- Arisawa, Mieko,Suzuki, Takaaki,Ishikawa, Tomofumi,Yamaguchi, Masahiko
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supporting information; scheme or table
p. 12214 - 12215
(2009/02/04)
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- New polysulfur-nitrogen heterocycles by thermolysis of 1, 3λ4δ2,2,4-benzodithiadiazines in the hydrocarbon and fluorocarbon series
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In contrast to thermolysis of 1,3λ4δ2,2, 4-benzodithiadiazine (1) and its 5,6,7,8-tetrafluoro derivative 2 in dilute (10-3 M) hydrocarbon solutions, which leads to persistent 1,2,3-benzodithiazolyls in nearly quantitative
- Zhivonitko, Vladimir V.,Makarov, Alexander Yu.,Bagryanskaya, Irina Yu.,Gatilov, Yuri V.,Shakirov, Makhmut M.,Zibarev, Andrey V.
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p. 4099 - 4108
(2007/10/03)
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- Synthesis of fluorophosphoranes via the mitsunobu reaction
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Treatment of triphenylphosphine with potassium hydrogen fluoride or hydrogen fluoridepyridine and diisopropyl azodicarboxylate in acetonitrile or tetrahydrofuran, at room temperature results in the clean formation of difluorotriphenylphosphorane. Analogous results were obtained with other phosphines such as tributylphosphine and tris(dimethylamino) phosphine.
- Harvey, Peta J.,Jenkins, Ian D.
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p. 9775 - 9778
(2007/10/02)
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- Low temperature fluorination of some non-metals and non-metal compounds with fluorine
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Low temperature fluorination with elemental fluorine of elemental phosphorus, sulphur, silicon, amorphous carbon and phosphorus trichloride, phosphorus pentoxide, triphenylphosphine, hexafluorodisilane, hexachlorodisilane, hexabromodisilane, tetrasulphur tetranitride, sulphur dioxide, thionyl chloride and sulphuryl chloride has been carried out in freon-11 medium.The corresponding fluoro compounds have been isolated in near quanititative yields, purified by low temperature fractional condensation and characterised by IR spectroscopy and elemental analysis.
- Padma, D K,Kalbandkeri, R G,Suresh, B S,Bhat, V Subrahmanya
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p. 172 - 176
(2007/10/02)
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- In situ generation of 2,3-diaryltetrazolinlidenes: Trapping experiments and ring opening to 1-cyanoazimines
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The redox system formazanide ion/tetrazolium ion, realized as an ECE sequence, is as a to manipulate both electron-deficient and -surplus centers attached to the of electronically. In order to introduce this redox substituent as a nucleophilic entity into
- Lowack, Rainer H.,Weiss, Robert
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p. 333 - 338
(2007/10/02)
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- STERICALLY HINDERED PENTACOORDINATED PHOSPHORUS AND SILICON COPMPOUNDS
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The synthesis and X-ray structures of the first examples of five-coordinated acyclic derivatives of phosphorus and silicon incorporating the bulky substituents, the 1-naphthyl and t-butyl groups, are reported.Increases in bond distances induced by steric
- Holmes, Robert R.,Chandrasekhar, V.,Day, Roberta O.,Harland, John J.,Payne, Jeffrey S.,Holmes, Joan M.
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p. 409 - 412
(2007/10/02)
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- BEITRAEGE ZUR CHEMIE DES IODOPENTAFLUORIDS. TEIL IV. IF5 EIN SELEKTIVES OXIDATIVES FLUORIERUNGSMITTEL FUER ORGANOPHOSPHOR(III)-VERBINDUNGEN
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Aryl-and alkylphosphines R3P, R2PF, R2PCl, and RPCl2 are oxidized by IF5 to the corresponding fluorophosphoranes in a fast one step-reaction at or below 0 deg C.The only coproduct is elemental iodine.IF3 or IF as reduction products of IF5 are not observed.Fission of P-C - bonds by from I2 and IF5 is negligible under reaction conditions.In alkylfluorophosphoranes fluoride donor-acceptor-interactions between fluorophosphoranes and IF5 are observed.
- Frohn, H. J.,Maurer, H.
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- Carbonyl Difluoride: a Versatile Fluorinating Reagent
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Carbonyl difluoride is a readily accessible reagent for introducing fluorine into molecules by oxidative addition to the central atom or by displacement of hydrogen from P-H, N-H, or C-H bonds.
- Gupta, O. D.,Shreeve, Jean'ne M.
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p. 416 - 417
(2007/10/02)
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