- Catalytic trifluoromethylation of iodoarenes by use of 2-trifluoromethylated benzimidazoline as trifluoromethylating reagent
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The trifluoromethylation of iodoarenes was accomplished by use of a 2-trifluoromethylbenzimidazoline derivative as the trifluoromethylating reagent and a catalytic amount of Cu(I) in the presence of 2,2'-bipyridyl as the ligand. Through a mechanistic study, we found that the oxidative addition of the iodoarene to the Cu(I)–CF3 species is the rate-determining step.
- Akiyama, Takahiko,Ishikawa, Taisuke,Kamiyama, Nanami,Uchikura, Tatsuhiro
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supporting information
p. 2442 - 2447
(2020/11/07)
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- NITRATION
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The present invention relates to a process for preparing a nitrated compound, comprising the step of reacting a compound (A) comprising at least one substituted or unsubstituted aromatic or heteroaromatic ring, wherein said heteroaromatic ring comprises at least one heteroatom selected from the group consisting of oxygen, sulfur, phosphor, selenium and nitrogen, with a compound of formula (I) wherein Y is selected from the group consisting of hydrogen and nitro.
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Page/Page column 36; 37; 47; 66-67; 38; 49-50; 42; 65-66
(2020/05/28)
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- N-Nitroheterocycles: Bench-Stable Organic Reagents for Catalytic Ipso-Nitration of Aryl- And Heteroarylboronic Acids
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Photocatalytic and metal-free protocols to access various aromatic and heteroaromatic nitro compounds through ipso-nitration of readily available boronic acid derivatives were developed using non-metal-based, bench-stable, and recyclable nitrating reagents. These methods are operationally simple, mild, regioselective, and possess excellent functional group compatibility, delivering desired products in up to 99% yield.
- Budinská, Alena,Katayev, Dmitry,Passera, Alessandro,Zhang, Kun
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supporting information
(2020/03/30)
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- Au@ZnO Core-Shell: Scalable Photocatalytic Trifluoromethylation Using CF3CO2Na as an Inexpensive Reagent under Visible Light Irradiation
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Trifluoromethylation is of significant importance for the synthesis of many small molecules vital for medicinal and agrochemical research. The importance of the CF3 group as well as the related synthetic challenges is so evident that many reagents have been reported for the synthesis of trifluoromethylated compounds, but these typical reagents are expensive and the methods for preparing them are difficult. Here, we report a new scalable and operationally simple trifluoromethylation reaction using sodium trifluoroacetate as a reagent and Au-modified ZnO as a photocatalyst under visible light irradiation. The reaction proceeds via trifluoromethylation of a broad range of aryl halides, arylboronic acids, and arene and heteroarene substrates. Some pharmaceutical and agrochemical compounds have been trifluoromethylated directly to demonstrate the applicability of the method.
- Bazyar, Zahra,Hosseini-Sarvari, Mona
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supporting information
p. 2345 - 2353
(2019/10/16)
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- Preparation method of substituted nitrobenzene compound
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The invention discloses a preparation method of a substituted nitrobenzene compound. The method comprises the following steps: carrying out a decarboxylation reaction as shown below on a compound II under the action of alkali in a solvent at the temperature of 150 to 250 DEG C to obtain a compound I; the alkali is one or more of carbonates and bicarbonates of alkali metals. Compared with some metal-catalyzed decarboxylation methods, the preparation method of the substituted nitrobenzene compound has the advantages of simple operation, low production cost, convenient post-treatment and high yield, and more application values in industrial production.
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Paragraph 0050-0053
(2019/03/29)
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- Ligand-free trifluoromethylation of iodoarenes by use of 2-Aryl-2-trifluoromethylbenzimidazoline as new trifluoromethylating reagent
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N-Methyl 2-aryl-2-trifluoromethylbenzimidazolines were synthesized and utilized in the trifluoromethylation reaction of iodoarenes in the presence of copper(I) salt and base. Iodoarenes bearing electron-donating and electron-withdrawing groups were tolerant to this reaction in the absence of a ligand and gave trifluorotoluene derivatives in good to high yields.
- Miyagawa, Masamichi,Ishikawa, Taisuke,Shinkai, Kota,Akiyama, Takahiko
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supporting information
p. 29 - 31
(2019/01/04)
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- Nucleophilic trifluoromethylation of electron-deficient arenes
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A novel trifluoromethylation of arenes is presented, which proceeds under mild reaction conditions and has the potential for late-stage functionalisation of pharmaceuticals and agrochemicals. The new reaction allows for the regioselective conversion of nitroarenes into 1,2-trifluoromethylated nitroarenes, via a C-H activation pathway. Furthermore, a substitution of nitroarenes to trifluoromethyl arenes is also presented.
- Pike, Jack A.,Walton, James W.
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supporting information
p. 9858 - 9861
(2017/09/11)
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- DBU-Promoted Trifluoromethylation of Aryl Iodides with Difluoromethyltriphenylphosphonium Bromide
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DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide (DFPB) in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P+CF2-, but also converts the difluorocarbene generated from ylide Ph3P+CF2- into trifluoromethyl anion, finally resulting in the trifluoromethylation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.
- Wei, Yun,Yu, Liuying,Lin, Jinhong,Zheng, Xing,Xiao, Jichang
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p. 481 - 484
(2016/06/01)
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- Trifluoromethylation of haloarenes with a new trifluoro-methylating reagent Cu(O2CCF2SO2F)2
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A new trifluoromethylating reagent Cu(O2CCF2SO2F)2, which easily decomposes to generate active CuCF3 species in DMF at room temperature, has been conveniently prepared from inexpensive starting materials on a large scale. This new reagent can be applied to efficiently trifluoromethylate a variety of haloarenes under mild conditions, providing good-to-excellent yields of the desired products.
- Zhao, Gang,Wu, Hao,Xiao, Zhiwei,Chen, Qing-Yun,Liu, Chao
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p. 50250 - 50254
(2016/06/15)
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- Copper-catalysed synthesis of trifluoromethyl(hetero)arenes from di(hetero)aryl-λ3-iodanes
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An efficient synthesis of trifluoromethylated (hetero)arenes has been achieved through the regioselective copper-catalyzed trifluoromethylation of di(hetero)aryl-λ3-iodanes, employing readily available trifluoromethyltrimethylsilane. The reaction works well for both symmetrical and unsymmetrical di(hetero)aryl-λ3-iodanes with good regioselectivity and also tolerates diverse functional groups such as bromo, iodo, cyano, nitro, ester, ketone and enolizable ketone.
- Pandey, Vinay Kumar,Anbarasan, Pazhamalai
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p. 18525 - 18529
(2016/02/27)
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- Mechanism of trifluoromethylation of aryl halides with CuCF3and the ortho effect
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A combined experimental (radical clock, kinetic, Hammett) and computational (DFT, MM) study of the trifluoromethylation reaction of aryl halides with CuCF3 reveals a nonradical mechanism involving Ar-X oxidative addition to the Cu(I) center as the rate determining step. The reaction is second order, first order in each reactant with ΔG? ≈ 24 kcal/mol for PhI (computed ΔG? = 21.9 kcal/ mol). An abrupt change in the gradient on the Hammett plot of log(kR/ kH) versus σp for 11 p-RC6H4I substrates produces two correlations (ρ = +0.69 and +1.83), which is temptingly suggestive of two different reaction pathways. Only one mechanism is operational, however, as advocated by a single linear correlation with σp- (ρ = +0.91), analysis of the experimental ρ values, close similarity of the transition states varying in R and displaying clear signs of -M interactions, and excellent reproduction of the plot by DFT. The long-known yet previously uncomprehended ortho effect has been quantified, for the first time, using the reaction of CuCF3 with a series of o-RC6H4Br: R(kR/kH) = H (1) 2Me (850) 2 (4300) 2H (150 000). With minor contributions from electronic factors, the ortho effect is largely determined by (i) the stabilizing coordination of the o-substituent to Cu in the transition state with the Cu?O distance varying directly with the barrier and (ii) the steric bulk of the o-substituent that raises the ground state free energy of the haloarene (Go ortho - Go H or Go ortho - Go para) by inflicting molecular strain and consequently weakening the Ar-X bond.
- Konovalov, Andrey I.,Lishchynskyi, Anton,Grushin, Vladimir V.
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supporting information
p. 13410 - 13425
(2015/03/30)
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- Trifluoromethylation of aryl and heteroaryl halides with fluoroform-derived CuCF3: Scope, limitations, and mechanistic features
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Fluoroform-derived CuCF3 recently discovered in our group exhibits remarkably high reactivity toward aryl and heteroaryl halides, performing best in the absence of extra ligands. A broad variety of iodoarenes undergo smooth trifluoromethylation with the ligandless CuCF3 at 23-50 C to give the corresponding benzotrifluorides in nearly quantitative yield. A number of much less reactive aromatic bromides also have been trifluoromethylated, including pyridine, pyrimidine, pyrazine, and thiazole derivatives as well as aryl bromides bearing electron-withdrawing groups and/or ortho substituents. Only the most electrophilic chloroarenes can be trifluoromethylated, e.g., 2-chloronicotinic acid. Exceptionally high chemoselectivity of the reactions (no side-formation of arenes, biaryls, and C2F5 derivatives) has allowed for the isolation of a large number of trifluoromethylated products in high yield on a gram scale (up to 20 mmol). The CuCF3 reagent is destabilized by CuX coproduced in the reaction, the magnitude of the effect paralleling the Lewis acidity of CuX: CuCl > CuBr > CuI. While SNAr and SRN1 mechanisms are not operational, there is a well-pronounced ortho effect, i.e., the enhanced reactivity of ortho-substituted aryl halides 2-RC6H4X toward CuCF3. Intriguingly, this ortho-effect is observed for R = NO2, COOH, CHO, COOEt, COCH3, OCH3, and even CH3, but not for R = CN. The fluoroform-derived CuCF3 reagent and its reactions with haloarenes provide an unmatched combination of reactivity, selectivity, and low cost.
- Lishchynskyi, Anton,Novikov, Maxim A.,Martin, Eddy,Escudero-Adan, Eduardo C.,Novak, Petr,Grushin, Vladimir V.
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p. 11126 - 11146
(2013/12/04)
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- Copper-catalyzed aromatic trifluoromethylation via group transfer from fluoral derivatives
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Starting from a readily available fluoral derivative, catalytic aromatic trifluoromethylation has been successfully achieved. A small amount of copper(I) iodide-phenanthroline complex catalyzed the cross-coupling reactions of aryl/heteroaryl iodides with the O-silylated hemiaminal of fluoral (trifluoroacetaldehyde) to provide trifluoromethylated arenes in moderate to high yields.
- Kondo, Hideaki,Oishi, Masahiro,Fujikawa, Kenichi,Amii, Hideki
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supporting information; experimental part
p. 1247 - 1252
(2011/07/08)
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- Ethylammonium nitrate (EAN)/Tf2O and EAN/TFAA: Ionic liquid based systems for aromatic nitration
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Acting as in situ sources of triflyl nitrate (TfONO2) and trifluoroacetyl nitrate (CF3COONO2), the EAN/Tf 2O and EAN/TFAA systems, generated via metathesis in the readily available ethylammonium nitrate (EAN) ionic liquid as solvent, are powerful electrophilic nitrating reagents for a wide variety of aromatic and heteroaromatic compounds. Comparative nitration experiments indicate that EAN/Tf2O is superior to EAN/TFAA for nitration of strongly deactivated systems. Both systems exhibit low substrate selectivity (K T/KB = 5-10) in (Figure presented) between values reported for covalent nitrates and preformed nitronium salts.
- Aridoss, Gopalakrishnan,Laali, Kenneth K.
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experimental part
p. 8088 - 8094
(2011/11/13)
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- Preparation and characterization of diazenyl quinolin-8-ol with trifluoromethyl substituents
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The synthesis and properties of new monoazo dyes derived from the diazonium salts of 2-trifluoromethyl phenylamine and 4-chloro-3-trifluoromethyl phenylamine are considered.
- Yazdanbakhsh, Mohammad R.,Mahmoodi, Nosrat O.,Dabiry, Shahram
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p. 192 - 194
(2007/10/03)
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- Electrophilic tetraalkylammonium nitrate nitration. II. Improved anhydrous aromatic and heteroaromatic mononitration with tetramethylammonium nitrate and triflic anhydride, including selected microwave examples
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A new one-pot nitration employing tetramethylammonium nitrate and trifluoromethanesulfonic anhydride in dichloromethane to provide a ready source of the nitronium triflate nitrating agent is presented. Rapid and selective nitration with a variety of aromatic and heteroaromatic substrates is achieved resulting in the synthesis of several novel organic compounds. A distinct advantage is the removal of undesired byproducts by aqueous workup. This very mild nitration permits large-scale syntheses and gives high isolated product yields that often require no further purification. This tetramethylammonium nitrate-based nitration also has been applied to microwave-assisted conditions, and the results with several compounds are outlined.
- Shackelford, Scott A.,Anderson, Mark B.,Christie, Lance C.,Goetzen, Thomas,Guzman, Mark C.,Hananel, Martha A.,Kornreich, Wayne D.,Li, Haitao,Pathak, Ved P.,Rabinovich, Alex K.,Rajapakse, Ranjan J.,Truesdale, Larry K.,Tsank, Stella M.,Vazir, Haresh N.
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p. 267 - 275
(2007/10/03)
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- Electrophilic nitration of aromatics in ionic liquid solvents
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Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Huenig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3·Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.
- Laali,Gettwert
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- Aromatic trifluoromethyldenitration and trifluoromethyldecyanation using trifluoromethyltrimethylsilane
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Activation of trifluoromethyltrimethylsilane by potassium fluoride in N,N-dimethylacetamide provides a powerful source of trifluoromethide which is capable of substituting aromatic nitro and cyano groups under nucleophilic conditions, albeit in low yield. The trifluoromethide generated in this system is also a potent base which leads to a number of interesting side reactions via deprotonation of the substrate.
- Adams, Dave J.,Clark, James H.,Hansen, Liv B.,Sanders, Victoria C.,Tavener, Stewart J.
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p. 3081 - 3085
(2007/10/03)
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- Chemistry of superacids: 35. * NO2Cl-3MXN systems: Superelectrophilic aprotic nitrating agents for deactivated aromatics
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Superelectrophilic nitration of deactivated aromatics with NO2Cl-3MXn complexes in aprotic nonpolar solvents such as CH2Cl2 makes it possible to obtain the corresponding nitro derivatives in good to almost quantitative yields under mild conditions.
- Olah,Orlinkov,Ramaiah,Oxyzoglou,Prakash
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p. 924 - 927
(2007/10/03)
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- Electrochemical trifluoromethylation of aromatic compounds
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It was shown that the current yield of the products of anodic trifluoromethylation of arenes correlates with the adsorptivity and the rate of electrooxidation of arenes on the surface of a platinum electrode.
- Grinberg,Lundgren,Sterlin,Mysov
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p. 1131 - 1135
(2007/10/03)
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- A novel non-acidic method for the preparation of 2,2,2-trifluoro-1-(3-nitrophenyl)ethanone and 1-nitro-3-trifluoromethylbenzene, versatile starting materials for trifluoromethyl-containing aromatic compounds
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Treatment of 2,2,2-trifluoro-1-phenylethanone (1) and α,α,α-trifluorotoluene (3) with ozone or ozonized air in chlorinated hydrocarbons in the presence of excess nitrogen dioxide and a catalytic amount of iron(III) salt at -10-0°C leads to the respective title nitro compounds 2 and 4 in good to excellent yields. The reaction is clean and rapid, little or no hydrolysis of the trifluoromethyl group being observed during the nitration.
- Suzuki,Tatsumi,Suzuki,Maeda
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p. 1353 - 1354
(2007/10/02)
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- Electrosynthesis of (trifluoromethyl)copper complexes from bromotrifluoromethane: reactivities with various organic halides
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The synthesis of (trifluoromethyl)copper complexes is achieved easily by electroreduction of bromotrifluoromethane in N,N-dimethylformamide, in the presence of a sacrificial copper anode and various potential ligands.Three (trifluoromethyl)copper species are considered; two copper(II) and one copper(I).The mechanism of formation of the (trifluoromethyl)copper species is discussed and a study of their reactivities towards various organic halides is reported. Keywords: Copper; Trifluoromethyl derivatives; Electroreduction; Mechanism; Bromotrifluoromethane; (Trifluoromethyl)copper complexes
- Paratian, J. M.,Labbe, E.,Sibille, S.,Perichon, J.
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p. 137 - 144
(2007/10/02)
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- Aluminum chloride catalyzed nitration of aromatics with sodium nitrate/chlorotrimethyl-silane
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A mixture of sodium nitrate and chlorotrimethylsilane in the presence of anhydrous aluminum trichloride is a convenient nitration system for aromatic compounds. Nitryl chloride is formed as an intermediate in the reactions.
- Olah,Ramaiah,Sandford,Orlinkov,Prakash
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p. 468 - 469
(2007/10/02)
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- Generation of trifluoromethylcopper from chlorodifluoroacetate
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In the presence of fluoride ion, methyl chlorodifluoroacetate undergoes halide ion-promoted decarboxylation to give trifluoromethide which can be trapped with cuprous iodide.The resulting trifluoromethyl copper reagent has been observed spectroscopically and can be trapped with aryl iodides to give the corresponding trifluoromethylaromatic compound.
- MacNeil, James G.,Burton, Donald J.
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p. 225 - 228
(2007/10/02)
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- THE TRIFLUOROMETHYLATION OF CHLOROAROMATICS USING THE COPPER-CF2Br2-DIALKYLAMIDE REACTION SYSTEM
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The in situ generation of CuCF3 from the reaction of copper, dibromodifluoromethane and either N,N-dimethylformamide or N,N-dimethylacetamide (Burton's reagent) has been used for the direct substitution of chlorine by CF3 in a number of aromatic substrates.Particular attention has been paid to the effects of ring substituents on the efficiency of reaction.
- Clark, James H.,Denness, James E.,McClinton, Martin A.,Wynd, Andrew J.
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p. 411 - 426
(2007/10/02)
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- THE EFFECT OF CHARCOAL ON THE TRIFLUOROMETHYLATION OF ARYL CHLORIDES USING BURTON'S REAGENT
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The reactivity of the trifluoromethylating system copper-dibromodifluoromethane-N,N-dimethylacetamide towards aryl chlorides can be enhanced by the addition of charcoal.
- Clark, James H.,McClinton, Martin A.,Jones, Craig W.,Landon, Philip,Bishop, D.,Blade, R. J.
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p. 2133 - 2136
(2007/10/02)
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- The Direct Trifluoromethylation of Aryl Chlorides using Burton's Reagent
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The copper-dibromodifluoromethane-N,N-dimethylacetamide reaction system trifluoromethylates electronically activated aryl chlorides possessing ortho groups capable of interacting with the metal.
- Clark, James H.,McClinton, Martin A.,Blade, Robert J.
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p. 638 - 639
(2007/10/02)
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- Process for the preparation of compounds containing a difluoromethylene or trifluoromethyl group
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A process for the preparation of compounds containing a difluoromethylene or trifluoromethyl group. A compound containing a carbonyl group, preferbly an acid, acid halide, amide, ketone or any compound containing a perhaloalkylcarbonyl moiety is placed, in anhydrous liquid hydrofluoric acid, in contact with boron trifluoride in a quantity such that the absolute pressure of boron trifluoride in the reaction system is at least one bar for a time sufficient to convert the carbonyl group to a difluormethylene or trifluoromethyl group. The compounds obtained are useful as synthesis intermediates in the pharmaceutical, plant-protection and dye industries, as anesthetics or as heat-transfer and lubricating fluids.
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