- Halogenated method of aromatic compound
-
The invention belongs to the field of organic synthesis, and particularly relates to synthesis of aromatic halogens, in particular to arylamine. The invention discloses a synthesis method of a corresponding ortho-halogenated product from aromatic compounds such as carbazole and phenol. The method comprises the following steps: adding a metal sulfonate salt catalyst, aromatic amine, carbazole, phenol and other hydrogen - heteroatom-containing aromatic compound reaction substrates, a halogenation reagent and a reaction solvent at a specific reaction temperature. After the drying agent is dried, the yield of the reaction product and the nuclear magnetic characterization determining structure are determined by column chromatography. The reaction product yield is determined by gas chromatography. By adopting the method, under the cheap metal salt catalyst, a plurality of ortho-substituted brominated and chloro products can be obtained with moderate to excellent yield.
- -
-
Paragraph 0070-0073
(2021/11/10)
-
- Convenient One-Pot Synthesis of 9 H -Carbazoles by Microwave Irradiation Employing a Green Palladium-Based Nanocatalyst
-
An efficient palladium-catalyzed tandem reaction for the one-pot synthesis of 9 H -carbazoles under microwave irradiation is developed. This approach involves a sequential Buchwald-Hartwig amination and a direct arylation from affordable and inexpensive anilines and 1,2-dihaloarenes. For the development of this purpose, a novel and magnetically recoverable palladium nanocatalyst supported on a green biochar under ligand-free conditions is used. Compared to other existing palladium-based protocols, the present synthetic methodology shows a drastic reduction in reaction times and excellent compatibility with different functional groups allowing to obtain a small library of 9 H -carbazoles in high yields and with good regioselectivity. This procedure represents the first example in the direct synthesis of carbazoles using a heterogeneous palladium nanocatalyst from commercial precursors. To examine the application of this protocol, a direct and scalable synthesis of the bioactive carbazole alkaloid clausenalene from commercially available starting materials is described.
- Steingruber, H. Sebastián,Mendioroz, Pamela,Volpe, María A.,Gerbino, Darío C.
-
p. 4048 - 4058
(2021/08/03)
-
- Direct para-Selective C-H Amination of Iodobenzenes: Highly Efficient Approach for the Synthesis of Diarylamines
-
Iodine(III)-mediated synthesis of 4-iodo-N-phenylaniline from iodobenzene has been achieved, and the reaction can proceed under mild conditions. A variety of functional groups were well tolerated, providing the corresponding products in moderate to good yields. The remaining iodine group provides an effective platform for converting the products into several valuable asymmetric diphenylamines. Most importantly, this reaction can be easily scaled up to the ten-gram scale, highlighting its synthetic utility. The mechanistic study revealed that the in situ generated aryl hypervalent iodine intermediate is the key factor to realize this para-selective C-H amination reaction.
- Chen, Yujie,Huang, Zhibin,Jiang, Yaqiqi,Shu, Sai,Yang, Shan,Shi, Da-Qing,Zhao, Yingsheng
-
p. 8226 - 8235
(2021/06/28)
-
- Reductive C?N Coupling of Nitroarenes: Heterogenization of MoO3 Catalyst by Confinement in Silica
-
The construction of C?N bonds with nitroaromatics and boronic acids using highly efficient and recyclable catalysts remains a challenge. In this study, nanoporous MoO3 confined in silica serves as an efficient heterogeneous catalyst for C?N cross-coupling of nitroaromatics with aryl or alkyl boronic acids to deliver N-arylamines and with desirable multiple reusability. Experimental results suggest that silica not only heterogenizes the Mo species in the confined mesoporous microenvironment but also significantly reduces the reaction induction period and regulates the chemical efficiency of the targeted product. The well-shaped MoO3@m?SiO2 catalyst exhibits improved catalytic performance both in yield and turnover number, in contrast with homogeneous Mo catalysts, commercial Pd/C, or MoO3 nanoparticles. This approach offers a new avenue for the heterogeneous catalytic synthesis of valuable bioactive molecules.
- Yang, Fu,Dong, Xuexue,Shen, Yang,Liu, Mengting,Zhou, Hu,Wang, Xuyu,Li, Lulu,Yuan, Aihua,Song, Heng
-
p. 3413 - 3421
(2021/07/31)
-
- A quinoxaline-based porous organic polymer containing copper nanoparticles CuNPs@Q-POP as a robust nanocatalyst toward C-N coupling reaction
-
A novel porous organic polymer (denoted by Q-POP) was successfully fabricated by free-radical copolymerization of allyl-substituted 2,3-di(2-hydroxyphenyl)1,2-dihydroquinoxaline, and divinylbenzene under solvothermal conditions and used as a new platform for immobilization of copper nanoparticles. The CuNPs@Q-POP nanocatalyst was prepared via incorporating of Cu(NO3)2 into the polymeric network, followed by the reduction of Cu2+ ion with hydrazine hydrate. The obtained materials were characterized through FT-IR, XRD, N2 adsorption-desorption isotherms, ICP, TGA, SEM, HR-TEM, EDX, and the single-crystal X-ray crystallography. The results displayed that Q-POP and CuNPs@Q-POP possessed high surface area, hierarchical porosity, and excellent thermal and chemical stability. The as-synthesized catalyst was utilized for the Ullmann C-N coupling reaction of aromatic amines and different aryl halides to prepare various diarylamine derivatives. All types of aryl halides (except aryl fluorides) were screened in the Ullmann C-N coupling reaction with aromatic amines to produce diaryl amines in good to excellent yields (50-98%), and it turned out that aryl iodides have the best results. Besides, due to the strong interactions between CuNPs, N, and O-atoms of quinoxaline moiety existing in the polymeric framework, the copper leaching from the support was not observed. Furthermore, the catalyst was recycled and reused for five consecutive runs without significant activity loss.
- Gorginpour, Forough,Zali-Boeini, Hassan,Rudbari, Hadi Amiri
-
p. 3655 - 3665
(2021/02/03)
-
- Synthesis and characterization of new square planar heteroleptic cationic complexes [Ni(ii) β-oxodithioester-dppe]+; Their use as a catalyst for Chan-Lam coupling
-
Novel heteroleptic [Ni(ii) β-oxodithioester-dppe]+PF6- complexes (β-oxodithioester = methyl-3-hydroxy-3-benzyl-2-propenedithioate L1 1, methyl-3-hydroxy-3-(p-methoxyphenyl)-2-propenedithioate L2 2, methyl-3-hydroxy-3-(naphthyl)-2-propenedithioate L3 3, methyl-3-hydroxy-3-(p-chlorophenyl)-2-propenedithioate L4 4, methyl-3-hydroxy-3-(p-bromophenyl)-2-propenedithioate L5 5 and methyl-3-hydroxy-3-(p-cyanophenyl)-2-propenedithioate L6 6) have been synthesized and characterized by elemental (C, H, N) analysis, ESI-MS, IR, UV-visible, 1H, 13C{1H}, 31P{1H} and 19F{1H} NMR spectroscopy. The distorted square planar structures of the isomorphous cationic complexes 2, 3, 4 and 5 have been determined by X-ray crystallography. The catalytic activities of 1-6 were investigated for the Chan-Lam coupling reaction involving arylboronic acids and amines to afford N-arylated products in good to excellent yields under mild conditions with 1 mol% catalyst loading. This catalytic protocol offers significant functional group tolerance, and is endowed with a broad substrate scope. This journal is
- Kumari, Kavita,Kumar, Saurabh,Singh, Krishna Nand,Drew, Michael G. B.,Singh, Nanhai
-
p. 12143 - 12153
(2020/07/30)
-
- Copper-catalyzed, ceric ammonium nitrate mediated N-arylation of amines
-
Cu-Catalyzed, ligand- and base-free cross-coupling of aryl boronic acids with primary and secondary amines has been reported. This ‘Chan-Evans-Lam' reaction has revealed that at room temperature, with a catalytic amount of copper(ii) acetate and ceric ammonium nitrate (CAN) as an oxidant, N-arylation can result in an effective C-N bond formation. This air stable, practical, robust protocol enables tolerance towards a variety of functional groups on both boronic acid and amine partners.
- Gonela, Uma Maheshwar,Ablordeppey, Seth Y.
-
supporting information
p. 2861 - 2864
(2019/02/17)
-
- Reductive Molybdenum-Catalyzed Direct Amination of Boronic Acids with Nitro Compounds
-
The synthesis of aromatic amines is of utmost importance in a wide range of chemical contexts. We report a direct amination of boronic acids with nitro compounds to yield (hetero)aryl amines. The novel combination of a dioxomolybdenum(VI) catalyst and triphenylphosphine as inexpensive reductant has revealed to be decisive to achieve this new C?N coupling. Our methodology has proven to be scalable, air and moisture tolerant, highly chemoselective and engages both aliphatic and aromatic nitro compounds. Moreover, this general and step-economical synthesis of aromatic secondary amines showcases orthogonality to other aromatic amine syntheses as it tolerates aryl halides and carbonyl compounds.
- Suárez-Pantiga, Samuel,Hernández-Ruiz, Raquel,Virumbrales, Cintia,Pedrosa, María R.,Sanz, Roberto
-
supporting information
p. 2129 - 2133
(2019/01/25)
-
- Ligand-Free Iron-Catalyzed C-F Amination of Diarylamines: A One-Pot Regioselective Synthesis of Diaryl Dihydrophenazines
-
A one-pot synthesis of various 5,10-diaryl-5,10-dihydrophenazines (DADHPs) from diarylamines has been achieved by using an iron-catalyzed C-F amination. Homodimerization of magnesium diarylamides, followed by defluorinative intramolecular cyclization (dou
- Aoki, Yuma,O'Brien, Harry M.,Kawasaki, Hiroto,Takaya, Hikaru,Nakamura, Masaharu
-
supporting information
(2019/01/21)
-
- Ligand-Free Iron-Catalyzed C-F Amination of Diarylamines: A One-Pot Regioselective Synthesis of Diaryl Dihydrophenazines
-
A one-pot synthesis of various 5,10-diaryl-5,10-dihydrophenazines (DADHPs) from diarylamines has been achieved by using an iron-catalyzed C-F amination. Homodimerization of magnesium diarylamides, followed by defluorinative intramolecular cyclization (dou
- Aoki, Yuma,O'Brien, Harry M.,Kawasaki, Hiroto,Takaya, Hikaru,Nakamura, Masaharu
-
supporting information
p. 461 - 464
(2019/01/23)
-
- One-pot synthesis of n-aryl-nicotinamides and diarylamines based on a tunable smiles rearrangement
-
A one-pot Smiles rearrangement has been developed as a useful protocol for the straightforward synthesis of diverse N-aryl-nicotinamides. This method also provides chemoselective access toward diarylamines based on the different substitutions of the amide group. The potential application of the transformation is exemplified by the synthesis of an on-market succinate dehydrogenase inhibitor, boscalid. A substituent-mediated Smiles rearrangement to N-aryl-nicotinamides and diarylamines has been developed. In addition to the wide range of heterocyclic building blocks, the one-pot process also provides an efficient access to an on-market fungicide, boscalid.
- Liu, Shihui,Zhu, Shaofan,Wu, Ying,Gao, Jiayu,Qian, Pengfei,Hu, Yanwei,Shi, Linsen,Chen, Shaohua,Zhang, Shilei,Zhang, Yinan
-
supporting information
p. 3048 - 3052
(2015/05/13)
-
- Utilizing Mor-DalPhos/palladium-catalyzed monoarylation in the multicomponent one-pot synthesis of indoles
-
The application of a Mor-DalPhos/palladium catalyst system in the one-pot, multicomponent assembly of substituted indoles from ortho-chlorohaloarenes, alkyl ketones (including acetone), and primary amines is reported. The described protocols offer improved substrate scope in all three reaction components, under more mild conditions and without the need for an additional drying agent. Also reported are the first examples of such multicomponent reactions where all reactants are combined at the start of the reaction, without the need for inert atmosphere reaction conditions.
- Rotta-Loria, Nicolas L.,Borzenko, Andrey,Alsabeh, Pamela G.,Lavery, Christopher B.,Stradiotto, Mark
-
p. 100 - 106
(2015/01/30)
-
- Synthesis and development of Chitosan anchored copper(II) Schiff base complexes as heterogeneous catalysts for N-arylation of amines
-
Abstract The Chitosan anchored Cu(II) Schiff base complexes (C1-C3) have been synthesized and characterized by FTIR, UV, FE-SEM, EDAX, TGA, AAS and elemental analysis. These complexes have been found to be efficient and recyclable heterogeneous catalysts for the Chan-Lam C-N coupling reaction of various aromatic/aliphatic amines with arylboronic acid under mild reaction conditions. These complexes can be easily filtered out from the reaction medium and reused up to five times without significant loss of catalytic activity.
- Anuradha,Kumari, Shweta,Pathak, Devendra D.
-
supporting information
p. 4135 - 4142
(2015/08/03)
-
- Solvent-free N-arylation of amines with arylboronic acids under ball milling conditions
-
Solvent-free coupling reactions of arylboronic acids with various amines were presented under ball milling conditions, achieving the aromatic amine coupling products with yields ranging from moderate to good. This type of mechano-chemistry exhibited advantages of solvent-free property, high efficiency, simple work-up procedure and eco-friendliness. This journal is the Partner Organisations 2014.
- Zhu, Xingyi,Zhang, Qihong,Su, Weike
-
p. 22775 - 22778
(2014/06/23)
-
- Palladium C-N bond formation catalysed by air-stable robust polydentate ferrocenylphosphines: A comparative study for the efficient and selective coupling of aniline derivatives to dichloroarene
-
The arylation of aniline derivatives with dichloroarenes under a low palladium content (below the currently used 5 to 10 mol%) was studied using nine different ferrocenylphosphine ligands, including the easily accessible 1,1′-bis(diphenylphosphino)ferrocene, DPPF. The electron-enriched air-stable tridentate ferrocenylpolyphosphine 1,2-bis(diphenylphosphino)- 1′-(diisopropylphosphino)-4-tert-butylferrocene, L5, employed in 2 mol% in combination with 1 mol% [PdCl(η3-C3H 5)]2 allows an efficient and selective coupling, while such demanding substrates currently induce chloroarene homocoupling and/or dehalogenation processes. The scope and limitation of the optimized system are explored, with a focus on electron-poor fluoroanilines (deactivated nucleophiles) and electron-rich methylated and methoxylated dichlorobenzenes (deactivated electrophiles). The Royal Society of Chemistry 2014.
- Platon, Melanie,Roger, Julien,Royer, Sylviane,Hierso, Jean-Cyrille
-
p. 2072 - 2080
(2014/06/24)
-
- Palladium-catalyzed formation of secondary and tertiary amines from aryl dihalides with air-stable ferrocenyl tri- and diphosphines: Synthesis and X-ray structure of efficient catalysts beyond [PdCl2(DPPF)]
-
Robust, air-stable tridentate and bidentate ferrocenylphosphines 1,2-bis(diphenylphosphino)-1′-(diisopropylphosphino)-4-tert- butylferrocene, L5, and 1,1′-bis(diisopropylphosphino)-3,3′- bis(tert-butyl)ferrocene, L9, combined with 1 mol% of [PdCl(η3- C3H5)]2 led to two new catalytic systems which allow the coupling of aniline derivatives with mono- and dihaloarenes to form functionalized diarylamines and triarylamines. The excellent selectivity of the reactions avoids the deleterious dehalogenation of the substrates and products. The X-ray structure characterization of the related complex [PdCl 2(L9)] is reported in which ligand L9 in its meso form is significantly distorted.
- Mom, Sophal,Platon, Mélanie,Cattey, Hélène,Spencer, Howard J.,Low, Paul J.,Hierso, Jean-Cyrille
-
-
- Ligand-free CuTC-catalyzed N-arylation of amides, anilines and 4-aminoantipyrine: Synthesis of N-arylacrylamides, 4-amido-N-phenylbenzamides and 4-amino(N-phenyl)antipyrenes
-
N-Arylation of amides and anilines with aryl iodides was efficiently catalyzed by copper thiophenecarboxylate under ligand-free conditions with good to excellent yields. A variety of substituted aryl iodides, amides, anilines and 4-aminoantipyrine were found to be applicable to the simple catalytic system. Furthermore, some practical, unique secondary amides, such as N-arylacrylamides and 4-amido-N-phenylbenzamides, and 4-amino(N-phenyl)antipyrenes, which are difficult to obtain by the classical methods, were prepared.
- Quan, Zheng-Jun,Xia, Hai-Dong,Zhang, Zhang,Da, Yu-Xia,Wang, Xi-Cun
-
-
- O-iodoxybenzoic acid mediated N-arylation of aromatic amines by using arylhydrazines as the arylating counterpart
-
Through free-radical trapping experiments we have established, for the first time, the combination of arylhydrazines with o-iodoxybenzoic acid (IBX) for the generation of aryl free radicals. On the basis of this finding, a method was developed for the N-arylation of aromatic amines under mild conditions (base-free, -5 °C) by using arylhydrazines as the arylating counterpart and arylamines. The scope of this method was demonstrated by using a number of arylhydrazines and arylamines, which gave the N-arylated amines in good yields. Through free-radical trapping experiments, the present work describes the combination of arylhydrazines with o-iodoxybenzoic acid (IBX) for the generation aryl free radicals. This finding is exploited in the development of a mild method for the N-arylation of arylamines by using arylhydrazines as the arylating agents. The scope of this method is demonstrated through a number of examples. Copyright
- Jadhav, Ravindra R.,Huddar, Sameerana N.,Akamanchi, Krishnacharya G.
-
supporting information
p. 6779 - 6783
(2013/11/06)
-
- Direct amination of phenols under metal-free conditions
-
Herein, we disclose the metal-free synthesis of arylamines via the direct amination of phenols using aminating reagents. This reaction procedure uses easy accessible aminating reagents and provides a versatile synthetic route to a broad range of arylamines with various functionalities in good to excellent yield. By using a two-step route of amination and oxidative coupling reaction, we synthesized three naturally occurring carbazole alkaloids: murrayafoline A, mukonine, and clausenine from two commercially available phenols. Georg Thieme Verlag Stuttgart · New York.
- Yu, Jianzhong,Wang, Yongtao,Zhang, Peizhi,Wu, Jun
-
supporting information
p. 1448 - 1454
(2013/07/26)
-
- Efficient catalytic aryl amination of bromoarenes using 3-iminophosphine palladium(II) chloride
-
While pursuing the development of new hydroamination catalysts, a 3-iminophosphine palladium(II) chloride complex [(3IP)PdCl2] was synthesized that has subsequently proven to be an effective precatalyst for the aryl amination of bromoarenes. This (3IP)PdCl2 complex has been utilized in the catalytic aryl amination of both bromobenzene and bromopyridine derivatives, specifically yielding excellent activity in coupling reactions involving bromobenzene, 4-bromotoluene, and 2-bromopyridine. Using a standard set of catalytic conditions, many alkyl and aryl amines have been investigated as coupling partners in the aryl amination of bromoarenes. In general, secondary alkyl amines and ortho-substituted anilines proved to be the best substrates for this reaction, commonly giving quantitative conversion to products, while primary amines and other anilines gave only poor to moderate results. Catalytic screening data, product yields, and full characterization of isolated products are included.
- Samblanet, Danielle C.,Schmidt, Joseph A. R.
-
p. 7 - 18,12
(2012/12/12)
-
- Synthesis of carbazoles by intramolecular arylation of diarylamide anions
-
(Chemical Equation Presented) The synthesis of a series of substituted 9H-carbazoles by the photostimulated SRN1 substitution reaction with diarylamines as starting substrate was performed. The diarylamines were obtained by two approaches, the Pd-catalyzed reactions (Buchwald-Hartwig) or Cu-catalyzed reactions of 2-haloanilines with aryl halides, or 2-bromoiodobenzene with anilines, with moderate to very good isolated yields (45-89%). Through an intramolecular C-C bond formation of diarylamines by the SRN1 mechanism, carbazoles were achieved. These reactions proceeded synthetically in very good to excellent yields (81-99%) in liquid ammonia and DMSO. The reaction of N-(2-bromophenyl)-2-phenylbenzenamine gave 1-phenyl-9H-carbazole (38%) and the isomer 9H-tribenz[b,d,f]azepine (58%). By using this methodology, 9Hcarbazoles, substituted 9H-carbazoles, benzocarbazoles, and even 3,3′-bi(9H-carbazole) were obtained by a double SRN1 reaction with benzidine.
- Buden, Maria E.,Vaillard, Victoria A.,Martin, Sandra E.,Rossi, Roberto A.
-
experimental part
p. 4490 - 4498
(2009/09/26)
-
- Rhodium-catalyzed silylation and intramolecular arylation of nitriles via the silicon-assisted cleavage of carbon-cyano bonds
-
A rhodium-catalyzed silylation reaction of carbon - cyano bonds using disilane has been developed. Under these catalytic conditions, carbon-cyano bonds in aryl, alkenyl, allyl, and benzyl cyanides bearing a variety of functional groups can be silylated. The observation of an enamine side product in the silylation of benzyl cyanides and related stoichiometric studies indicate that the carbon-cyano bond cleavage proceeds through the deinsertion of silyl isocyanide from η2-iminoacyl complex B. Knowledge gained from these studies has led to the development of a new intramolecular biaryl coupling reaction in which aryl cyanides and aryl chlorides are cross-coupled.
- Tobisu, Mamoru,Kita, Yusuke,Ano, Yusuke,Chatani, Naoto
-
supporting information; experimental part
p. 15982 - 15989
(2009/05/16)
-
- Synthesis of diarylamines catalyzed by iron salts
-
A study was conducted to demonstrate the synthesis of diarylamines catalyzed by iron salts. The study evaluated the influence acetyl as an N-protecting group. The coupling of acetanilide and iodobenzene was selected as a model reaction, to optimize the reaction conditions. It was observed that a considerable amount of the N-deprotected compound was obtained along with the desired N-acetyl diarylamine. It was also observed that diphenylamine was isolated in a significant yield, by performing a basic hydrolysis with NaOMe after the iron-catalyzed arylation. A one-pot synthesis of diphenylamine was performed by adding NaOMe to the N-arylation reaction mixture, after the acetanilide was consumed completely. It was demonstrated that the strategy overcomes the synthetic limitations associated with poor reactivity of aromatic amines under iron catalysis and serves as an alternative approach for the preparation of diarylamines.
- Correa, Arkaitz,Carril, Monica,Bolm, Carsten
-
supporting information; experimental part
p. 10919 - 10922
(2009/11/30)
-
- Expedited palladium-catalyzed amination of aryl nonaflates through the use of microwave-irradiation and soluble organic amine bases
-
Microwave-assisted, palladium-catalyzed C-N bond-forming reactions with aryl/heteroaryl nonaflates and amines using the soluble amine bases DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) or MTBD (7-methyl-1,5,7-triazabicyclo[4.4. 0]dec-5-ene) and ligands (1-3) resulted in good to excellent yields (71-99%) of arylamines in short reaction times (1-45 min).
- Tundel, Rachel E.,Anderson, Kevin W.,Buchwald, Stephen L.
-
p. 430 - 433
(2007/10/03)
-
- High-yielding intramolecular direct arylation reactions with aryl chlorides
-
(Chemical Equation Presented) An N-heterocyclic carbene palladium catalyst system is used to promote direct arylation of a broad range of aryl chlorides to form six- and five-membered ring biaryls. An influence of the halide on the palladium precatalyst on catalyst activation has been revealed, as has a beneficial effect of NHC salts that allows the turnover numbers to be increased by simple addition of imidazolium salts to the reaction mixture.
- Campeau, Louis-Charles,Thansandote, Praew,Fagnou, Keith
-
p. 1857 - 1860
(2007/10/03)
-
- The surprisingly facile thermal dehalogenation of chlorinated aromatics by a hydroaromatic donor solvent. Tautomerization of chlorinated phenols and anilines
-
Up to 600 K, chlorinated benzenes and naphthalenes are inert in a hydrogen atom donating solvent such as 9,10-dihydroanthracene. However, when a hydroxyl or amine group is attached to the 2 or 4 position relative to chlorine, a surprisingly facile and selective hydrodehalogenation occurs at temperatures between 530 and 630 K. These features are the result of the onset of tautomeric equilibria for the chlorophenols or -anilines, creating the corresponding enones or imines, respectively, as reactive intermediates. The mechanism of dehalogenation involves the rate-determining transfer of a hydrogen atom from the solvent to the reactive intermediate according to a reverse radical disproportionation (RRD), followed by elimination of chlorine. The reactivity of mono- and dichlorophenols, chloroanilines, 4-chloro-1-naphthol, and 4-chloro-1-naphthylamine dissolved in 9,10-dihydroanthracene has been investigated. By means of density functional theory (DFT) calculations, the energies for the tautomers and their hydrogen affinities have been established. The experimental selectivities could be adequately reproduced by the computed data.
- Mulder, Peter,Arends, Isabel W. C. E.,Santoro, Danilo,Korth, Hans-Gert
-
p. 4247 - 4257
(2007/10/03)
-
- Palladium-Catalyzed Amination of Aryl Nonaflates
-
The first detailed study of the palladium-catalyzed amination of aryl nonaflates is reported. Use of ligands 2-4 and 6 allows for the catalytic amination of electron-rich and -neutral aryl nonaflates with both primary and secondary amines. With use of Xantphos 5, the catalytic amination of a variety of functionalized aryl nonaflates resulted in excellent yields of anilines; even 2-carboxymethyl aryl nonaflate is effectively coupled with a primary alkylamine. Moderate yields were obtained when coupling halo-aryl nonaflates with a variety of amines, where in most cases the aryl nonaflate reacted in preference to the aryl halide. Overall, aryl nonaflates are an effective alternative to triflates in palladium-catalyzed C-N bond-forming processes due to their increased stability under the reaction conditions.
- Anderson, Kevin W.,Mendez-Perez, Maria,Priego, Julian,Buchwald, Stephen L.
-
p. 9563 - 9573
(2007/10/03)
-
- N- and C-attacks on aromatics of phenylnitrenium ion generated from N-phenylhydroxylamine in the presence of trifluoroacetic acid containing polyphosphoric acid or trifluoroacetic anhydride
-
A phenylnitrenium ion formed from N-phenylhydroxylamine in the presence of trifluoroacetic acid (TFA) containing polyphosphoric acid (PPA) interacts with the counterion -O2CCF3 and the unshared electron-pair of H2O, showing Hammett's ρ values -5.2 and -4.0 for N- and C-attacks on aromatics PhX (X = H, Me, Et, Ph and Cl), respectively. The ratio N-/C-attack for this nitrenium ion is lower than for the nitrenium ion interacting with only the counterion; the latter nitrenium ion is generated by the use of trifluoroacetic anhydride (TFAA) instead of PPA or by reaction of phenyl azide with aromatics in TFA. The ratio for the former nitrenium ion is affected by the aromatic substituent X:X = Me > X = Et > X = Ph > X = H > X = OMe at 20 and 50°C. The order for X = Cl is between those of X = H and X = Ph at 20°C, but highest at 50°C. The ratio is increased by higher reaction temperature and by decreased concentration of TFA. The results are demonstrated from the mechanistic viewpoint for the nitrenium ions.
- Takeuchi, Hiroshi,Taniguchi, Tomohito,Ueda, Takahiro
-
p. 295 - 300
(2007/10/03)
-
- The synthesis and reaction of heterocyclic thiophosphoryl chlorides with ALCL3 or CF3SO3Ag. An attempt to obtain λ5σ3-thiophosphoryl cations
-
Two new heterocyclic thiophosphoryl chlorides (2), derivatives of 1,3,2-benzodiazaphosphole, are synthesized. The reaction of respective thiophosphoryl chlorides (1) and (2) with AlCl3 affords dimeric heterocyclic diphosphonium dications 3and 4
- Huang, Tian-Bao,Yu, Xiao-Ming,Liu, Lingfei,Wang, Ke
-
-
- Sterically Hindered N-Aryl-2(1H)-Quinolones and N-Aryl-6(5H)-Phenanthridinones: Separation of Enantiomers and Barriers to Racemization
-
The novel N-aryl-4-chloro-3-methyl-2(1H)-quinolones (1)-(4) have been synthesized by condensation of the appropriate diphenylamine with diethyl methylmalonate and subsequent chlorination of the resulting N-aryl-4-hydroxy-3-methyl-2(1H)-quinolones (7)-(10). 5-(1-Naphthyl)-6(5H)-phenanthridinone (5) has been synthesized by the Chapman rearrangement of the 6-(1-naphthoxy)phenanthridine (11).Separation of the enantiomers (M) and (P) of the quinolones (1)-(4) and phenanthridinones (5), (6) was achieved by liquid chromatography on triacetylcellulose.The barriers to partial rotation about the C-N bond in (1)-(6) were determined by thermal racemization of enantiomers and are compared with those of structurally related molecules.
- Mintas, Mhaden,Mihaljevic, Vesna,Koller, Helmut,Schuster, Doris,Mannschreck, Albrecht
-
p. 619 - 624
(2007/10/02)
-
- N- and C-Attacks of Phenylnitrenium Ions Generated from Phenyl Azides in the Presence of Trifluoroacetic Acid and/or Trifluoromethanesulphonic Acid
-
Phenylnitrenium ions were generated from phenyl azides in the presence of trifluoroacetic acid (TFA) and/or trifluoromethanesulphonic acid (TFSA).Unsubstituted phenylnitrenium ions and those with an electron-withdrawing group such as NO2 or CN undergo aromatic N-substitution, whereas those with an electron-donating group such as Me, OMe, CH2Ph, or Ph undergo C-substitution, hydrogen abstraction, and tar formation.The special character of TFA and TFSA as compared with other acids is discussed.
- Takeuchi, Hiroshi,Takano, Katsuyuki
-
p. 611 - 618
(2007/10/02)
-
- Aromatic Substitution by Phenylnitrenium and Naphthylnitrenium Ions formed from Phenyl Azide and 1-Azidonaphthalene in the Presence of Trifluoromethanesulphonic Acid
-
Aromatic N-substitution by phenylnitrenium ions generated from phenyl azide in the presence of a catalytic amount of trifluoromethanesulphonic acid gave diarylamines (in especially good yield in the reaction with biphenyl or naphthalene), whereas naphthylnitrenium ions from 1-azidonaphthalene react with benzene to afford a C-substitution product, 1-amino-4-phenylnaphthalene.
- Takeuchi, Hiroshi,Takano, Katsuyuki
-
p. 447 - 449
(2007/10/02)
-