- Liquid-phase fluorination of aromatic compounds by elemental fluorine
-
The fluorination of aromatic compounds (benzene, toluene, phenol and benzoic acid) by elemental fluorine diluted with nitrogen has been investigated in various solvents (Freon 11, chloroform, methanol, trifluoroacetic acid, 2,2,2-trifluoroethanol, water) in order to define the influence of the experimental conditions on the reaction.Experiments have been carried out by varying the temperature, the substrate concentration in solution, the molar ratio of fluorine to substrate, and the concentration of fluorine in the fluorine/nitrogen mixture.In all cases, the effects on the yield of fluorinated products were studied.Monofluorinated compounds were mainly found in the reaction mixture, the isomers formed being in accord with the mechanism for electrophilic substitution.The highest yield of monofluorinated products was obtained with polar solvents and the following order was found: CFCl3 CHCl3 CH3OH CF3CH2OH CF3COOH.Interesting results were also found using particular additives (for instance, KOH or C4F9SO3Na in methanol) or water as the solvent.A direct relationship was observed between the yield of monofluorinated compounds and the molar ratio of fluorine to substrate, which has to be less than one in order to obtain high yields.In contrast, low selectivity, expressed as the yield ratio of ortho to para (or meta) isomers, was found. - Keywords: Fluorination; Aromatic compounds; Elemental fluorine; Isomer formation; Solvent effects; Additive effects
- Conte, L.,Gambaretto, G. P.,Napoli, M.,Fraccaro, C.,Legnaro, E.
-
-
Read Online
- Direct fluorination of toluene using elemental fluorine in gas/liquid microreactors
-
Direct fluorination of toluene, pure or dissolved in either acetonitrile or methanol, using elemental fluorine was investigated in gas/liquid microreactors, namely a falling film microreactor and a micro bubble column. The experiments included measurements at high substrate concentrations and at high fluorine contents diluted in a nitrogen carrier gas, e.g. up to 50vol.% fluorine. Results obtained were compared to the performance of a laboratory bubble column which served as a technological benchmark. Due to the formation of liquid layers of only a few tens of micrometers thickness, the microreactors provide very large interfacial areas, e.g. up to 40,000m2/m3. These values exceed by far those of the laboratory bubble column as well as all other devices applied in practice. The potential for enhancing mass and heat transfer was verified by several experiments resulting in an increase in conversion and selectivity for the microreactors compared to the laboratory benchmark. For the falling film microreactor, yields of up to 28% of monofluorinated ortho and para products for a degree of toluene conversion of 76% were obtained. These values are of the same order as described for the industrially applied Schiemann process. Space-time yields of the microreactors, when referred to the reaction channel volume, were orders of magnitude higher than those of the laboratory bubble column. Taking into account the construction material needed, the corresponding figures of merit, for an idealized geometry as well as the existing total reactor geometry, still indicate technological and economic benefits. A variation of operating conditions for the direct fluorination revealed that conversion can be increased in the microreactors by using higher fluorine-to-toluene ratios and reaction temperatures. The choice of solvent is also essential, with acetonitrile yielding much better results than methanol.
- J?hnisch,Baerns,Hessel,Ehrfeld,Haverkamp,L?we,Wille,Guber
-
-
Read Online
- Gas-phase alkylation of fluorobenzene and substituted fluorobenzene by (CH3)2F+ ions
-
The gas-phase methylation of selected fluorobenzenes by (CH3)2F+ ions has been investigated by a combination of mass spectrometric and radiolytic techniques. The results are compared with those of related alkylation reactions, both in the gas phase and in solution.
- Attina,Ricci
-
-
Read Online
- Exhaustive chlorination of [B12H12]2- without chlorine gas and the use of [B12Cl12]2- as a supporting anion in catalytic hydrodefluorination of aliphatic C-F bonds
-
The fully chlorinated closo-dodecaborate salt Cs2[B 12Cl12] was prepared in high yield from Cs 2[B12H12] and SO2Cl2 in acetonitrile at refluxing temperature. [Ph3C]2[B 12Cl12] was obtained by simple metathesis reactions. Catalytic hydrodefluorination of benzotrifluoride sp3 C-F bonds was accomplished using [Ph3C]2[B12Cl12] as a precatalyst and Et3SiH as a stoichiometric reagent. Full consumption of the sp3 C-F bonds in p-FC6H 4CF3 and C6F5CF3 with a turnover number up to 2000 was achieved.
- Gu, Weixing,Ozerov, Oleg V.
-
-
Read Online
- Full continuous flow synthesis process of fluorine-containing aromatic hydrocarbon compounds
-
The invention provides a full continuous flow synthesis process of a fluorine-containing aromatic hydrocarbon compound, and belongs to the technical field of preparation of halogenated hydrocarbon carbocyclic organic compounds. Arylamine and hydrogen fluoride are pumped into a thermostat A and a thermostat B respectively and flow into a micro-channel reactor C for a salt forming reaction after constant temperature treatment, and a sulfuric acid solution of nitrosyl sulfuric acid is pumped into a thermostat D and flows into a micro-channel reactor E together with a salt forming product flowing out of the micro-channel reactor C for a diazotization reaction after constant temperature treatment. A product flows into a micro-channel reactor F to be subjected to a thermal decomposition reaction, is cooled by a cooler G and then enters a three-phase separator H to be continuously separated, nitrogen is discharged after being subjected to spraying deacidification, a fluorine-containing aromatic hydrocarbon crude product is subjected to continuous alkali washing, continuous drying and continuous rectification to obtain a fluorine-containing aromatic hydrocarbon finished product, and a hydrofluoric acid and sulfuric acid mixture is subjected to continuous distillation to obtain a product. The hydrogen fluoride and sulfuric acid are obtained. The full continuous flow synthesis process has the advantages of high reaction yield, excellent product quality, good production safety, less pollutant discharge and the like.
- -
-
Paragraph 0081-0094
(2021/04/07)
-
- A Mild, General, Metal-Free Method for Desulfurization of Thiols and Disulfides Induced by Visible-Light
-
A visible-light-induced metal-free desulfurization method for thiols and disulfides has been explored. This radical desulfurization features mild conditions, robustness, and excellent functionality compatibility. It was successfully applied not only to the desulfurization of small molecules, but also to peptides.
- Qiu, Wenting,Shi, Shuai,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
-
supporting information
p. 1255 - 1258
(2021/05/05)
-
- Coupling Photocatalysis and Substitution Chemistry to Expand and Normalize Redox-Active Halides
-
Photocatalysis can generate radicals in a controlled fashion and has become an important synthetic strategy. However, limitations due to the reducibility of alkyl halides prevent their broader implementation. Herein we explore the use of nucleophiles that can substitute the halide and serve as an electron capture motif that normalize the variable redox potentials across substrates. When used with photocatalysis, bench-stable, commercially available collidinium salts prove to be excellent radical precursors with a broad scope.
- Rathnayake, Manjula D.,Weaver, Jimmie D.
-
supporting information
p. 2036 - 2041
(2021/04/05)
-
- Ruthenium-catalyzed selective hydroboronolysis of ethers
-
A ruthenium-catalyzed reaction of HBpin with substituted organic ethers leads to the activation of C?O bonds, resulting in the formation of alkanes and boronate esters via hydroboronolysis. A ruthenium precatalyst, [Ru (p-cymene)Cl]2Cl2 (1), is employed, and the reactions proceed under neat conditions at 135 °C and atmospheric pressure (ca. 1.5 bar at 135 °C). Unsymmetrical dibenzyl ethers undergo selective hydroboronolysis on relatively electron-poor C?O bonds. In arylbenzyl or alkylbenzyl ethers, C?O bond cleavage occurs selectively on CBn?OR bonds (Bn = benzyl); in alkylmethyl ethers, selective deconstruction of CMe?OR bonds leads to the formation of alkylboronate esters and methane. Cyclic ethers are also amenable to catalytic hydroboronolysis. Mechanistic studies indicated the immediate in situ formation of a mono-hydridobridged dinuclear ruthenium complex [{(η6-p-cymene)RuCl}2(μ?H?μ?Cl)] (2), which is highly active for hydroboronolysis of ethers. Over time, the dinuclear species decompose to produce ruthenium nanoparticles that are also active for this transformation. Using this catalytic system, hydroboronolysis could be applied effectively to a very large scope of ethers, demonstrating its great potential to cleave C?O bonds in ethers as an alternative to traditional hydrogenolysis.
- Kaithal, Akash,Kalsi, Deepti,Krishnakumar, Varadhan,Pattanaik, Sandip,Bordet, Alexis,Leitner, Walter,Gunanathan, Chidambaram
-
p. 14390 - 14397
(2020/12/21)
-
- A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
-
Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
- Feng, Boya,Yang, Yudong,You, Jingsong
-
p. 6031 - 6035
(2020/07/10)
-
- 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
-
p. 313 - 317
(2020/01/28)
-
- Hydrodehalogenation of organohalides by Et3SiH catalysed by group 4 metal complexes and B(C6F5)3
-
Catalytic hydrodehalogenation (HDH) of aliphatic organohalides such as trifluorotoluenes by Et3SiH proceeds in the presence of readily available group 4 metal compounds: Cp′2MX2 (Cp′ = η5-C5H5 or η5-C5Me5; X = F, Cl, or Me; M = Ti, Zr, or Hf), CpTiCl3 and TiCl4 with a catalytic amount of B(C6F5)3. The use of metallocenes in combination with the borane activator leads to a better selectivity of the reaction, i.e., suppression of Friedel-Crafts alkylations of arenes.
- ?ilková, Nadě?da,Dunlop, David,Horá?ek, Michal,Lama?, Martin,Pinkas, Ji?í
-
supporting information
p. 2771 - 2775
(2020/03/13)
-
- Phosphonic acid mediated practical dehalogenation and benzylation with benzyl halides
-
For the first time, by using H3PO3/I2 system, various benzyl chlorides, bromides and iodides were dehalogenated successfully. In the presence of H3PO3, benzyl halides underwent electrophilic substitution reactions with electron-rich arenes, leading to a broad range of diarylmethanes in good yields. These transformations feature green, cheap reducing reagents and metal-free conditions. A possible mechanism was proposed.
- Gao, Jing,Han, Li-Biao,Ma, Yonghao,Tang, Zilong,Wu, Xiaofang,Xiao, Jing
-
p. 22343 - 22347
(2019/07/31)
-
- Connecting Organometallic Ni(III) and Ni(IV): Reactions of Carbon-Centered Radicals with High-Valent Organonickel Complexes
-
This paper describes the one-electron interconversions of isolable NiIII and NiIV complexes through their reactions with carbon-centered radicals (R?). First, model NiIII complexes are shown to react with alkyl and aryl radicals to afford NiIV products. Preliminary mechanistic studies implicate a pathway involving direct addition of a carbon-centered radical to the NiIII center. This is directly analogous to the known reactivity of NiII complexes with R?, a step that is commonly implicated in catalysis. Second, a NiIV-CH3 complex is shown to react with aryl and alkyl radicals to afford C-C bonds via a proposed SH2-type mechanism. This pathway is leveraged to enable challenging H3C-CF3 bond formation under mild conditions. Overall, these investigations suggest that NiII/III/IV sequences may be viable redox pathways in high-oxidation-state nickel catalysis.
- Bour, James R.,Ferguson, Devin M.,McClain, Edward J.,Kampf, Jeff W.,Sanford, Melanie S.
-
supporting information
p. 8914 - 8920
(2019/06/13)
-
- Photocatalytic carbanion generation-benzylation of aliphatic aldehydes to secondary alcohols
-
We present a redox-neutral method for the photocatalytic generation of carbanions. Benzylic carboxylates are photooxidized by single electron transfer; immediate CO2 extrusion and reduction of the in situ formed radical yields a carbanion capable of reacting with aliphatic aldehydes as electrophiles giving the Grignard analogous reaction product.
- Donabauer, Karsten,Maity, Mitasree,Berger, Anna Lucia,Huff, Gregory S.,Crespi, Stefano,K?nig, Burkhard
-
p. 5162 - 5166
(2019/06/05)
-
- Chemoselective Hydrodeoxygenation of Carboxylic Acids to Hydrocarbons over Nitrogen-Doped Carbon-Alumina Hybrid Supported Iron Catalysts
-
The establishment of catalyst systems for the chemoselective hydrodeoxygenation (HDO) of carboxylic acids to hydrocarbons, such as the HDO of long-chain fatty acids to alkanes, is important for biomass to biofuel conversion. As the most abundant and probably the cheapest transition metal on the earth, iron is a promising non-noble-metal alternative to precious metals for large-scale conversion of biomass. However, it usually suffers from unsatisfactory activity. In this work, a nitrogen-doped carbon-alumina hybrid supported iron (Fe-N-C@Al2O3) catalyst is established for chemoselective HDO of carboxylic acids to hydrocarbons. By using stearic acid HDO as the model reaction, n-octadecane and n-heptadecane are produced with yields of 91.9% and 6.0%, respectively. Triglycerides can also be converted into liquid alkanes with a total molar yield of >92%. In addition, the iron catalyst can chemoselectively catalyze the HDO of the carboxylic acid group in the presence of other functional groups such as an aromatic ring. This chemoselectivity has rarely been seen before because the aromatic ring is usually more easily hydrogenated in comparison to HDO of the carboxylic acid group. The characterization results showed that both the formation of a nitrogen-doped carbon-alumina hybrid and the iron loading are important for the Lewis basicity of these catalysts, in order to adsorb the acid substrates. The addition of melamine as the nitrogen precursor during pyrolysis eliminates undesired reactions between the iron precursor and alumina support to form an inactive hercynite phase, leading to the formation of an Fe3C active phase for the hydrogenation of -COOH to -CH2OH and the hybrid of N-C and alumina for the HDO of -CH2OH to -CH3.
- Li, Jiang,Zhang, Junjie,Wang, Shuai,Xu, Guangyue,Wang, Hao,Vlachos, Dionisios G.
-
p. 1564 - 1577
(2019/02/03)
-
- Reactions of Arylsulfonate Electrophiles with NMe4F: Mechanistic Insight, Reactivity, and Scope
-
This paper describes a detailed study of the deoxyfluorination of aryl fluorosulfonates with tetramethylammonium fluoride (NMe4F) and ultimately identifies other sulfonate electrophiles that participate in this transformation. 19F NMR spectroscopic monitoring of the deoxyfluorination of aryl fluorosulfonates revealed the rapid formation of diaryl sulfates under the reaction conditions. These intermediates can proceed to fluorinated products; however, diaryl sulfate derivatives bearing electron-donating substituents react very slowly with NMe4F. Based on these findings, aryl triflate and aryl nonaflate derivatives were explored, since these cannot react to form diaryl sulfates. Aryl triflates were found to be particularly effective electrophiles for deoxyfluorination with NMe4F, and certain derivatives (i.e., those bearing electron-neutral/donating substituents) afforded higher yields than their aryl fluorosulfonate counterparts. Computational studies implicate a similar mechanism for deoxyfluorination of all the sulfonate electrophiles.
- Schimler, Sydonie D.,Froese, Robert D. J.,Bland, Douglas C.,Sanford, Melanie S.
-
p. 11178 - 11190
(2018/09/12)
-
- Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
-
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
-
p. 9896 - 9900
(2018/07/31)
-
- Nickel-catalyzed C-O bond reduction of aryl and benzyl 2-pyridyl ethers
-
The reduction of aryl and benzyl 2-pyridyl ethers with sodium isopropoxide was carried out via nickel-catalyzed C-OPy bond cleavage, giving reductive products in reasonable to excellent yields. This method allowed the 2-pyridyloxy group to be directly rem
- Li, Jing,Wang, Zhong-Xia
-
p. 2138 - 2141
(2018/03/06)
-
- Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds
-
Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
- Stache, Erin E.,Ertel, Alyssa B.,Rovis, Tomislav,Doyle, Abigail G.
-
p. 11134 - 11139
(2018/11/21)
-
- 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)
-
- Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters
-
A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C-H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C-H bonds and is illustrated by late-stage methylation of four medicinally active compounds. In addition, reaction on a 200 mmol scale demonstrates reliability of this method. Mechanistic studies show that the reaction occurs by a slow release of methyl iodide by reaction of PO(OMe)3 with iodide catalyst, rather than the typical direct oxidative addition to a metal center. The low concentration of the reactive electrophile enables selective reaction with an arylcopper intermediate, rather than nucleophilic groups on the arylboronate, and binding of tert-butoxide to the boronate inhibits reaction of the electrophile with the tert-butoxide activator to form methyl ether.
- He, Zhi-Tao,Li, Haoquan,Haydl, Alexander M.,Whiteker, Gregory T.,Hartwig, John F.
-
supporting information
p. 17197 - 17202
(2018/12/14)
-
- An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
-
We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
- Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
-
p. 2250 - 2255
(2018/02/23)
-
- Manganese-Catalyzed Direct Deoxygenation of Primary Alcohols
-
Deoxygenation of alcohols is an important tool in the repertoire of defunctionalization methods in modern synthetic chemistry. We report the base-metal-catalyzed direct deoxygenation of benzylic and aliphatic primary alcohols via oxidative dehydrogenation/Wolff-Kishner reduction. The reaction is catalyzed by a well-defined PNP pincer complex of Earth-abundant manganese, evolving H2, N2, and water as the only byproducts.
- Bauer, Jonathan O.,Chakraborty, Subrata,Milstein, David
-
p. 4462 - 4466
(2017/07/24)
-
- METHOD FOR AROMATIC FLUORINATION
-
Disclosed is a fluorination method comprising providing an aryl fluorosuifonate and a fluorinating reagent to a reaction mixture; and reacting the aryl fluorosuifonate and the fluorinating reagent to provide a fluorinated aryl species. Also disclosed is a fluorination method comprising providing, a salt comprising a cation and an aryloxyiate, and SO2F2 to a reaction mixture; reacting the SO2F2 and the ammonium salt to provide a fluorinated aryl species. Further disclosed a fluorination method comprising providing a compound having the structure Ar-OH to a reaction mixture; where A is an aryl or heteroaryl; providing SO2F2 to the reaction mixture; providing a fluorinating reagent to the reaction mixture; reacting the SO2F2, the fluorinating reagent and the compound having the structure Ar-OH to provide a fluorinated aryl species having the structure Ar-F.
- -
-
Paragraph 0047-0049
(2017/12/18)
-
- Experimental and Computational Exploration of para-Selective Silylation with a Hydrogen-Bonded Template
-
The regioselective conversion of C?H bonds into C?Si bonds is extremely important owing to the natural abundance and non-toxicity of silicon. Classical silylation reactions often suffer from poor functional group compatibility, low atom economy, and insufficient regioselectivity. Herein, we disclose a template-assisted method for the regioselective para silylation of toluene derivatives. A new template was designed, and the origin of selectivity was analyzed experimentally and computationally. An interesting substrate–solvent hydrogen-bonding interaction was observed. Kinetic, spectroscopic, and computational studies shed light on the reaction mechanism. The synthetic significance of this strategy was highlighted by the generation of a precursor of a potential lipophilic bioisostere of γ-aminobutyric acid (GABA), various late-stage diversifications, and by mimicking enzymatic transformations.
- Maji, Arun,Guin, Srimanta,Feng, Sheng,Dahiya, Amit,Singh, Vikas Kumar,Liu, Peng,Maiti, Debabrata
-
supporting information
p. 14903 - 14907
(2017/10/30)
-
- Nucleophilic deoxyfluorination of phenols via aryl fluorosulfonate intermediates
-
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.
-
supporting information
p. 1452 - 1455
(2017/02/10)
-
- Nickel-catalyzed C-N bond reduction of aromatic and benzylic quaternary ammonium triflates
-
A nickel-catalyzed, efficient C-N bond reduction of aromatic and benzylic ammonium triflates has been developed using sodium isopropoxide as a reducing agent. The high efficiency, mild conditions, and good compatibility with various substituents made this method an effective supplement to the current catalytic hydrogenation reactions. Combining this reductive deamination reaction with directed aromatic functionalization reactions, a powerful strategy for regioselective functionalization of arenes was demonstrated using dialkylamine groups as traceless directing groups.
- Yi, Yuan-Qiu-Qiang,Yang, Wen-Cheng,Zhai, Dan-Dan,Zhang, Xiang-Yu,Li, Shuai-Qi,Guan, Bing-Tao
-
p. 10894 - 10897
(2016/09/09)
-
- Evidence for Direct Transmetalation of AuIII-F with Boronic Acids
-
The underlying reactivity of AuIII-F species with aryl boronic acids has been studied in detail taking advantage of four novel, stable difluoro-[(C^N)AuF2], arylmonofluoro-[(C^N)AuArF], and alkylmonofluoro-[(C^N)AuAlkF] gold(III) complexes, prepared and isolated in monomeric form. We provide the first experimental evidence for a direct AuIII-F/B transmetalation preceding the Csp2-Csp2 or Csp3-Csp2 bond formation.
- Kumar, Roopender,Linden, Anthony,Nevado, Cristina
-
supporting information
p. 13790 - 13793
(2016/11/06)
-
- Reactions of aromatic compounds with xenon difluoride
-
Reactions of substituted benzenes C6H5R (R = Me, F, Cl, Br, CF3, NO2) with xenon difluoride in the presence of boron trifluoride–diethyl ether complex in weakly acidic (1,1,1,3,3-pentafluorobutane) and weakly basic media (acetonitrile) have been studied. These reactions lead to the formation of fluorobenzene derivatives FC6H4R (isomer mixture) together with isomeric difluorobenzenes and fluorinated and non-fluorinated biphenyls. The results have been compared with previously reported data obtained in other solvents using other catalysts.
- Bardin,Adonin, N. Yu.
-
p. 1400 - 1407
(2016/11/29)
-
- Deoxygenation of carbonyl compounds using an alcohol as an efficient reducing agent catalyzed by oxo-rhenium complexes
-
This work describes the first methodology for the deoxygenation of carbonyl compounds using an alcohol as a green solvent/reducing agent catalyzed by oxo-rhenium complexes. The system 3-pentanol/ReOCl3(SMe2)(OPPh3) was successfully employed in the deoxygenation of several aryl ketones to the corresponding alkenes and also in the deoxygenation of aryl aldehydes to alkanes with moderate to excellent yields. The catalyst ReOCl3(SMe2)(OPPh3) can also be used in several catalytic cycles with good activity.
- Bernardo, Joana R.,Fernandes, Ana C.
-
supporting information
p. 2675 - 2681
(2016/05/24)
-
- Fluorination of aromatic compounds with xenon difluoride in the presence of boron trifluoride etherate
-
Fluorination of benzene with the XeF2 - BF3?Et2O system in acetonitrile at low temperatures affords fluorobenzene in 18% yield, the conversion of benzene being 92%. The rest products are di-, tri-, tetra-, and polyphenyls with different fluorination pattern. Toluene and chloro- and bromobenzenes are fluorinated predominantly at the ortho and para positions. Fluorination of 4-nitroanisole affords 2-fluoro-4-nitroanisole in 73% yield.
- Fedorov,Zubarev,Mortikov, V. Yu.,Rodinovskaya,Shestopalov
-
p. 1049 - 1052
(2016/02/09)
-
- METHOD FOR PRODUCING ORGANIC COMPOUND
-
PROBLEM TO BE SOLVED: To provide a method of subjecting a compound having on one carbon atom a carbon atom constituting a carbon-carbon double bond and a functional group such as a hydroxyl group to a reductive reaction condition and producing an organic compound having the functional group substituted with a hydrogen atom. SOLUTION: There is provided a method for producing a compound represented by a formula (50) from a raw material compound represented by a formula (10). The method includes a step of irradiating a reaction system with light, the reaction system comprising the raw material compound, a hydrogen source compound, and a catalyst having a palladium component supported by a carrier containing titanium oxide. (R11 to R15 are a hydrogen atom, a hydrocarbon group having 1 to 40 carbon atoms which may have a cyclic structure or a derivative group thereof, or a heteroatom-containing group having 1 to 20 carbon atoms which may have a cyclic structure or a derivative group thereof; and R16 is a hydrogen atom, a hydrocarbon group having 1 to 40 carbon atoms or an acyl group having 1 to 20 carbon atoms which may have a cyclic structure, or -CH(CH2OH)2).) COPYRIGHT: (C)2015,JPO&INPIT
- -
-
Paragraph 0084-0085; 0096-0097
(2018/10/16)
-
- Ruthenium-catalyzed nucleophilic fluorination of halobenzenes
-
The first π-coordination-catalyzed nucleophilic fluorination of unactivated aryl halides has been demonstrated. Chlorobenzene reacts with alkali metal fluorides (CsF, KF) in the presence of a Cp?Ru catalyst at 120-180°C to give fluorobenzene.
- Konovalov, Andrey I.,Gorbacheva, Evgeniya O.,Miloserdov, Fedor M.,Grushin, Vladimir V.
-
supporting information
p. 13527 - 13530
(2015/09/01)
-
- 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)
-
- 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
-
p. 9676 - 9681
(2015/01/08)
-
- Cross alkyl-aryl versus homo aryl-aryl coupling in palladium-catalyzed coupling of alkyl-gold(I) and aryl-halide
-
Experiments on palladium-catalyzed cross-coupling of [AuMe(PPh 3)] with aryl iodides show that Ar-Ar homocoupling products are the main product or an abundant byproduct of the reaction. The percentage of cross-coupling product is higher for aryls with a larger σp Hammet parameter. The scrambling of organic groups via bimetallic intermediates explains the formation of these products. This scrambling can be observed and the activation energies partially quantified in some cases using as aryl C 6Cl2F3, which is relatively reluctant to coupling.
- Carrasco, Desiree,Perez-Temprano, Monica H.,Casares, Juan A.,Espinet, Pablo
-
p. 3540 - 3545
(2014/08/05)
-
- Organometallic nickel(III) complexes relevant to cross-coupling and carbon-heteroatom bond formation reactions
-
Nickel complexes have been widely employed as catalysts in C-C and C-heteroatom bond formation reactions. In addition to Ni(0) and Ni(II) intermediates, several Ni-catalyzed reactions are proposed to also involve odd-electron Ni(I) and Ni(III) oxidation states. We report herein the isolation, structural and spectroscopic characterization, and organometallic reactivity of Ni(III) complexes containing aryl and alkyl ligands. These Ni(III) species undergo transmetalation and/or reductive elimination reactions to form new C-C or C-heteroatom bonds and are also competent catalysts for Kumada and Negishi cross-coupling reactions. Overall, these results provide strong evidence for the direct involvement of organometallic Ni(III) species in cross-coupling reactions and oxidatively induced C-heteroatom bond formation reactions.
- Zheng, Bo,Tang, Fengzhi,Luo, Jia,Schultz, Jason W.,Rath, Nigam P.,Mirica, Liviu M.
-
supporting information
p. 6499 - 6504
(2014/05/20)
-
- Off-rate screening (ORS) by surface plasmon resonance. An efficient method to kinetically sample hit to lead chemical space from unpurified reaction products
-
The dissociation rate constant kd (off-rate) is the component of ligand-protein binding with the most significant potential to enhance compound potency. Here we provide theoretical and empirical data to show that this parameter can be determined accurately from unpurified reaction products containing designed test compounds. This screening protocol is amenable to parallel chemistry, provides efficiencies of time and materials, and complements existing methodologies for the hit-to-lead phase in fragment-based drug discovery.
- Murray, James B.,Roughley, Stephen D.,Matassova, Natalia,Brough, Paul A.
-
supporting information
p. 2845 - 2850
(2014/05/06)
-
- Direct fluorination of cyclic carbonates and closo-K2[B 12H12] in a slug-flow ministructured reactor
-
A novel minireactor for direct fluorination of organic and inorganic substances was tested. The reactor consists of nickel-coated copper blocks with mechanically machined 1 mm channels and is equipped with an active cooling system. The direct fluorination of ethylene carbonate and propylene carbonate is described. For the fluorinated propylene carbonate, the NMR data of various fluorinated isomers were determined. The Gibbs reaction energies for the direct fluorination of ethylene and propylene carbonate were calculated at the reliable G3 level of theory. The excellent decomposition stability of the cyclic carbonates against high fluorine and HF concentrations also qualifies them as good solvents for direct fluorination processes, especially for ionic substrates. In this respect, the direct fluorination of the inorganic salt closo-K2[B12H12] in cyclic carbonates is presented.
- Hill, Mathias,Baron, Patrick,Cobry, Keith,Goll, Sascha K.,Lang, Philipp,Knapp, Carsten,Scherer, Harald,Woias, Peter,Zhang, Pengcheng,Krossing, Ingo
-
p. 292 - 301
(2013/08/23)
-
- Continuous flow reactor for Balz-Schiemann reaction: A new procedure for the preparation of aromatic fluorides
-
A facile and highly efficient procedure for the preparation of aromatic fluorides by Balz-Schiemann reaction via two continuous flow reactors has been set up. The continuous diazotization reactor was run at about 25 °C with residence times of 10-20 s, and the continuous fluorodediazoniation reactor was performed with a residence time of 1 min in high yields. The reaction times can be greatly reduced by increasing temperature and thereby taking advantage of superior mass and heat transfer of a continuous flow system.
- Yu, Zhi-Qun,Lv, Yan-Wen,Yu, Chuan-Ming,Su, Wei-Ke
-
p. 1261 - 1263
(2013/03/14)
-
- Aromatic fluoro-de-triazenation with boron trifluoride diethyl etherate under non-protic acid conditions
-
Fluoro-de-triazenation of 3,3-diethyl-1-aryltriazenes can be achieved by conventional or under microwave heating in carbon tetrachloride, in the presence of boron trifluoride diethyl etherate without any protic acid to avoid corresponding unwanted byproduct formation.
- Kovac, Mitja,Anderluh, Marko,Vercouillie, Johnny,Guilloteau, Denis,Emond, Patrick,Mavel, Sylvie
-
-
- 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)
-
- FLUORINATION OF ORGANIC COMPOUNDS
-
Methods for fluorinating organic compounds are described herein.
- -
-
Page/Page column 24
(2012/11/06)
-
- Intermolecular photodecarboxylation of electron-deficient substrates by phthalimides in water: Efficiency, selectivity and online monitoring
-
The intermolecular photodecarboxylation of arylacetic acids 3-5 in water by use of stoichiometric amounts of N-alkylated phthalimides 1a,b was investigated by NMR and online pH- and CO2-release sensing. Decreasing the electron donor capability of the arylacetic acids by 4-fluoro and trifluoromethyl substitution alters the efficiency of the photodecarboxylation and selectivity of the secondary reaction. A remarkable switch in reaction channel (A to B) was observed for perfluoropropionic acid.
- Griesbeck, Axel G.,Nazarov, Nestor,Neudoerfl, Joerg M.,Heffen, Maria
-
p. 3004 - 3006
(2013/01/15)
-
- Deoxyfluorination of phenols
-
An operationally simple ipso fluorination of phenols with a new deoxyfluorination reagent is presented.
- Tang, Pingping,Wang, Weike,Ritter, Tobias
-
supporting information; experimental part
p. 11482 - 11484
(2011/10/02)
-
- Silver-mediated fluorination of aryl silanes
-
A regiospecific silver-mediated fluorination of aryl silanes is reported. The reaction is operationally simple, and employs Ag2O as readily available, inexpensive silver source, which can be recovered.
- Tang, Pingping,Ritter, Tobias
-
supporting information; experimental part
p. 4449 - 4454
(2011/08/03)
-
- 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)
-
- Hydrodefluorination and other hydrodehalogenation of aliphatic carbon-halogen bonds using silylium catalysis
-
Trialkylsilylium cation equivalents partnered with halogenated carborane anions (such as Et3Si[HCB11H5Cl6]) function as efficient and long-lived catalysts for hydrodehalogenation of C-F, C-Cl, and C-Br bonds with trialkylsilanes as stoichiometric reagents. Only C(sp3)-halogen bonds undergo this reaction. The range of C-F bond-containing substrates that participate in this reaction is quite broad and includes simple alkyl fluorides, benzotrifluorides, and compounds with perfluoroalkyl groups attached to an aliphatic chain. However, CF4 has proven immune to this reaction. Hydrodechlorination was carried out with a series of alkyl chlorides and benzotrichlorides, and hydrodebromination was studied only with primary alkyl bromide substrates. Competitive experiments established a pronounced kinetic preference of the catalytic system for activation of a carbon-halogen bond of a lighter halide in primary alkyl halides. On the contrary, hydrodechlorination of C6F 5CCl3 proceeded much faster than hydrodefluorination of C6F5CF3 in one-pot experiments. A solid-state structure of Et3Si[HCB11H5Cl6] was determined by X-ray diffraction methods.
- Douvris, Christos,Nagaraja,Chen, Chun-Hsing,Foxman, Bruce M.,Ozerov, Oleg V.
-
supporting information; experimental part
p. 4946 - 4953
(2010/06/17)
-
- Process for the Synthesis of Highly Active Binary Metal Fluoride as a Fluorinating Agent for Aromatics
-
The subject invention relates to a process for the synthesis of highly active binary metal fluoride system for the fluorination of aromatic compounds. Fluorinated aromatic compounds are valuable synthons for the chemical synthesis of pharmaceutical drugs and novel polymers. Fluorobenzene is used to control carbon content in steel manufacturing, is an intermediate for pharmaceuticals, pesticides and other organic compounds. Fluorobenzene is typically produced by the reaction of aniline and sodium nitrite in the presence of hydrogen fluoride. The present invention relates to a process for the synthesis of highly active binary metal fluoride system consists of copper (II) fluoride and aluminum (III) fluoride for the fluorination of aromatic compounds in gas phase and recycling of the reagent, in situ, using O2 and HF.
- -
-
Page/Page column 6-7
(2010/02/17)
-
- FLUORINATION OF ORGANIC COMPOUNDS
-
Methods for fluorinating organic compounds are described herein.
- -
-
Page/Page column 104
(2010/07/10)
-
- Synthesis and studies of chemical properties of arylthallium(III) bis(tetrafluoroborates)
-
Synthesis of arylthallium(III)bis(tetrafluoroborates) was carried out and their pyrolysis was studied. Synthetic procedure for preparation of fluoroaromatic compounds is developed.
- Gun'kin
-
experimental part
p. 455 - 457
(2010/08/04)
-
- NO-CARRIER-ADDED NUCLEOPHILIC [F-18] FLUORINATION OF AROMATIC COMPOUNDS
-
Phenyliodonium ylide derivatives substituted with electron donating as well as electron withdrawing groups on the aromatic ring are shown for use as precursors in aromatic nucleophilic substitution reactions. The iodonium ylide group is substituted by nucleophiles such as halide ions to provide the corresponding haloaryl derivatives. No- carrier-added [F-18]fluoride ion exclusively substitutes the iodonium ylide moiety in these derivatives and provides high specific activity F- 18 labeled fluoro derivatives. Protected L-dopa-6-iodonium ylide derivative have been synthesized as a precursors for the preparation of no-carrier-added 6-[F- 18]fluoro-L-dopa. The iodonium ylide group in this L-dopa.derivative is nucleophilically substituted by no-carrier-added [F-18]fluoride ion to provide a [F-18]fluoro intermediates which upon acid hydrolysis yielded 6-[F- 18]fluoro-L-dopa.
- -
-
Page/Page column 11-12
(2010/11/03)
-