- Highly Active Ni Nanoparticles on N-doped Mesoporous Carbon with Tunable Selectivity for the One-Pot Transfer Hydroalkylation of Nitroarenes with EtOH in the Absence of H2
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Cost-effective and environmentally friendly conversion of nitroarenes into value-added products is desirable but still challenging. In this work, highly dispersed Ni nanoparticles (NPs) supported on N-doped mesoporous carbon (Ni/NC-x) were synthesized via novel ion exchange-pyrolysis strategy. Their catalytic performance was investigated for one-pot transfer hydroalkylation of nitrobenzene (NB) with EtOH in absence of H2. Interestingly, the catalytic performance could be easily manipulated by tuning the morphology and electronic state of Ni NPs via varying the pyrolysis temperature. It was found that the Ni/NC-650 achieved 100 % nitrobenzene conversion and approx. 90 % selectivity of N,N-diethyl aniline at 240 °C for 5 h, more active than those of homogeneous catalysts or supported Ni catalysts prepared by impregnation (Ni/NC-650-IM, Ni/SiO2). This can be ascribed to the higher dispersion and better reducibility as well as richer surface basicity of the catalyst. More interestingly, the Ni/NC-650 catalyst achieved complete conversion of various nitroarenes, yielding imines, secondary amines, or tertiary amines selectively by simply controlling the reaction temperature at 180, 200 and 240 °C, respectively. The one-pot hydrogen-free process with non-noble metal catalysts, as demonstrated in this work, shows great promise for selective conversion of nitroarenes with ethanol to various anilines at industrial scale, from an economic, environmental, and safety viewpoint.
- Tao, Yuewen,Nie, Yunqing,Hu, Haitao,Wang, Ke,Chen, Yi,Nie, Renfeng,Wang, Jianshe,Lu, Tianliang,Zhang, Yongsheng,Xu, Chunbao Charles
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p. 4243 - 4250
(2021/08/20)
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- Photocatalytic Water-Splitting Coupled with Alkanol Oxidation for Selective N-alkylation Reactions over Carbon Nitride
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Photocatalytic water splitting technology (PWST) enables the direct use of water as appealing “liquid hydrogen source” for transfer hydrogenation reactions. Currently, the development of PWST-based transfer hydrogenations is still in an embryonic stage. Previous reports generally centered on the rational utilization of the in situ generated H-source (electrons) for hydrogenations, in which photogenerated holes were quenched by sacrificial reagents. Herein, the fully-utilization of the liquid H-source and holes during water splitting is presented for photo-reductive N-alkylation of nitro-aromatic compounds. In this integrate system, H-species in situ generated from water splitting were designed for nitroarenes reduction to produce amines, while alkanols were oxidized by holes for cascade alkylating of anilines as well as the generated secondary amines. More than 50 examples achieved with a broad range scope validate the universal applicability of this mild and sustainable coupling approach. The synthetic utility of this protocol was further demonstrated by the synthesis of existing pharmaceuticals via selective N-alkylation of amines. This strategy based on the sustainable water splitting technology highlights a significant and promising route for selective synthesis of valuable N-alkylated fine chemicals and pharmaceuticals from nitroarenes and amines with water and alkanols.
- Xu, Yangsen,Zhang, Zhaofei,Qiu, Chuntian,Chen, Shaoqin,Ling, Xiang,Su, Chenliang
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p. 582 - 589
(2020/12/09)
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- A highly efficient Co-based catalyst fabricated by coordination-assisted impregnation strategy towards tandem catalytic functionalization of nitroarenes with various alcohols
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A well-defined hexamethylenetetramine (abbreviated as HMTA) based two-dimensional (2D) MOFs metalloligand (termed Zn-HMTA), with free uncoordinated tertiary amine groups, has been synthesized via solution diffusion method for the first time. The crystal structure of 2D Zn-HMTA metalloligand was determined by the single crystal X-ray diffraction (SCXRD). The SCXRD and X-ray photoelectron spectroscopy (XPS) analyses have revealed that the 2D Zn-HMTA metalloligand is rich in- free tertiary amine groups, which are of strong coordination ability to transition metal ions (e.g. Ni2+, Co2+, Zn2+, Cu2+). As a result, a 2D bimetallic Co@Zn-HMTA MOFs was synthesized via coordination-assisted impregnation (CAI) strategy attributed to the unique feature of strong coordinated ability of free tertiary amine groups. Furthermore, a series of self-supported Co-ZnO-CN nanocatalysts were afforded upon the as-synthesized Co@Zn-HMTA MOFs served as a self-sacrificial template for pyrolysis at different temperatures. The optimized catalyst (termed as Co-ZnO@CN-CAI) demonstrated the excellent catalytic performance for hydrogenation-alkylation tandem reaction in comparison with the classic ZnO@CN composite (derived from Zn-HMTA MOFs) supported metallic Co catalyst (Co-ZnO@CN-IWI) prepared by incipient wetness impregnation method. Moreover, the kinetic study was also performed to confirm that the alkylation is the rate-determining step in the hydrogenation-alkylation tandem reaction. The origin of enhanced catalytic performance of Co-ZnO@CN-CAI and the role of Co@Zn-HMTA MOFs precursor have been explored by way of various characterizations, e.g. HADDF-STEM-EDS, SEM-EDS, 13C MAS NMR, XRD, Raman and XPS, etc. It is anticipated that the prepared low-cost and easily prepared 2D Zn-HMTA metalloligand will become a general template for synthesis of highly self-supported catalysts with coordination-assisted impregnation strategy (CAI) for various catalytic reactions.
- Li, Guangming,Li, Jingfang,Li, Weizuo,Li, Xuewei,Li, Zhibin,Mao, Guijie,She, Wei,Wang, Jing
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p. 462 - 474
(2021/11/11)
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- Palladium Complexes Based on Ylide-Functionalized Phosphines (YPhos): Broadly Applicable High-Performance Precatalysts for the Amination of Aryl Halides at Room Temperature
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Palladium allyl, cinnamyl, and indenyl complexes with the ylide-substituted phosphines Cy3P+?C?(R)PCy2 (with R=Me (L1) or Ph (L2)) and Cy3P+?C?(Me)PtBu2 (L3) were prepared and applied as defined precatalysts in C?N coupling reactions. The complexes are highly active in the amination of 4-chlorotoluene with a series of different amines. Higher yields were observed with the precatalysts in comparison to the in situ generated catalysts. Changes in the ligand structures allowed for improved selectivities by shutting down β-hydride elimination or diarylation reactions. Particularly, the complexes based on L2 (joYPhos) revealed to be universal precatalysts for various amines and aryl halides. Full conversions to the desired products are reached mostly within 1 h reaction time at room temperature, thus making L2 to one of the most efficient ligands in C?N coupling reactions. The applicability of the catalysts was demonstrated for aryl chlorides, bromides and iodides together with primary and secondary aryl and alkyl amines, including gram-scale applications also with low catalyst loadings of down to 0.05 mol %. Kinetic studies further demonstrated the outstanding activity of the precatalysts with TOF over 10.000 h?1.
- Tappen, Jens,Rodstein, Ilja,McGuire, Katie,Gro?johann, Angela,L?ffler, Julian,Scherpf, Thorsten,Gessner, Viktoria H.
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supporting information
p. 4281 - 4288
(2020/03/13)
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- Iridium-Catalysed Reductive Deoxygenation of Ketones with Formic Acid as Traceless Hydride Donor
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An iridium-catalysed deoxygenation of ketones and aldehydes is achieved, with formic acid as hydride donor and water as co-solvent. At low catalyst loading, a number of 4-(N,N-disubstituted amino) aryl ketones are readily deoxygenated in excellent yields and chemoselectivity. Numerous functional groups, especially phenolic and alcoholic hydroxyls, secondary amine, carboxylic acid, and alkyl chloride, are well tolerable. Geminally dideuterated alkanes are obtained with up to 90% D incorporation, when DCO2D and D2O are used in place of their hydrogenative counterparts. The activating 4-(N,N-disubstituted amino)aryl groups have been demonstrated to undergo a variety of useful transformations. The deoxygenative deuterations have been used to prepare a deuterated drug molecule Chlorambucil-4,4-d2. (Figure presented.).
- Yang, Zhiheng,Zhu, Xueya,Yang, Shiyi,Cheng, Weiyan,Zhang, Xiaojian,Yang, Zhanhui
-
supporting information
p. 5496 - 5505
(2020/10/22)
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- Visible-Light-Enabled Direct Decarboxylative N-Alkylation
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The development of efficient and selective C?N bond-forming reactions from abundant feedstock chemicals remains a central theme in organic chemistry owing to the key roles of amines in synthesis, drug discovery, and materials science. Herein, we present a dual catalytic system for the N-alkylation of diverse aromatic carbocyclic and heterocyclic amines directly with carboxylic acids, by-passing their preactivation as redox-active esters. The reaction, which is enabled by visible-light-driven, acridine-catalyzed decarboxylation, provides access to N-alkylated secondary and tertiary anilines and N-heterocycles. Additional examples, including double alkylation, the installation of metabolically robust deuterated methyl groups, and tandem ring formation, further demonstrate the potential of the direct decarboxylative alkylation (DDA) reaction.
- Arman, Hadi D.,Dang, Hang T.,Haug, Graham C.,Larionov, Oleg V.,Nguyen, Viet D.,Nguyen, Vu T.,Vuong, Ngan T. H.
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supporting information
p. 7921 - 7927
(2020/04/10)
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- A Highly Active Ylide-Functionalized Phosphine for Palladium-Catalyzed Aminations of Aryl Chlorides
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Ylide-functionalized phosphine ligands (YPhos) were rationally designed to fit the requirements of Buchwald–Hartwig aminations at room temperature. This ligand class combines a strong electron-donating ability comparable to NHC ligands with high steric demand similar to biaryl phosphines. The active Pd species are stabilized by agostic C?H???Pd rather than by Pd–arene interactions. The practical advantage of YPhos ligands arises from their easy and scalable synthesis from widely available, inexpensive starting materials. Benchmark studies showed that YPhos-Pd complexes are superior to the best-known phosphine ligands in room-temperature aminations of aryl chlorides. The utility of the catalysts was demonstrated by the synthesis of various arylamines in high yields within short reaction times.
- Weber, Philip,Scherpf, Thorsten,Rodstein, Ilja,Lichte, Dominik,Scharf, Lennart T.,Goo?en, Lukas J.,Gessner, Viktoria H.
-
supporting information
p. 3203 - 3207
(2019/01/09)
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- A strategy of two-step tandem catalysis towards direct N-alkylation of nitroarenes with ethanol via facile fabricated novel Co-based catalysts derived from coordination polymers
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Three novel N-doped carbon supported Co/Co3O4 catalysts, namely, Co@CN-hmta, Co@CN-larg and Co-Co3O4@CN-bipy, with sheet-, worm-, honeycomb-like morphologies respectively, have been fabricated by the pyrolysis of well-defined coordination polymers (CPs). Upon the as-prepared catalysts were applied for the reaction of N-alkylation of nitroarenes with ethanol, a direct two-step tandem reaction is realized, in which the Co@CN-hmta delivers 100% conversion/selectivity of N-ethylaniline/N,N-diethylaniline from the direct N-alkylation of nitroarenes with ethanol. The kinetic studies were conducted to confirm that the N-alkylation of aniline with ethanol is the rate-determining step in the two-step tandem reaction. The SEM/EDX, XRD, Raman, TEM, XPS, and CO2-TPD characterization results have revealed that sizes and dispersion of metallic Co, amount of structural defects and surface Lewis basicity towards three catalysts can be tuned by changing the structures of Co-based CPs designed by different organic linkers, which may also help to understand the preparation of industrial catalysts on a molecular level. The optimized Co@CN-hmta catalyst is easily recycled by using the external magnet for successive reuses without any loss in both activity and selectivity. To the best of our knowledge, this is the first carbon-nitrogen species supported Co/Co3O4 catalysts derived from the CPs, which could effectively catalyzed the N-alkylation of nitroarenes with ethanol to produce the secondary amines and/or tertiary amines. This low-cost, recyclable and easy scale-up N-doped carbon supported catalyst may be of potential application in various heterogeneous catalytic reactions.
- Wang, Jing,Qi, Tianqinji,Li, Zhibin,She, Wei,Li, Xuewei,Li, Jingfang,Yan, Pengfei,Li, Weizuo,Li, Guangming
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p. 106 - 118
(2019/07/19)
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- Iridium-Catalyzed Highly Efficient and Site-Selective Deoxygenation of Alcohols
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An iridium-catalyzed, highly efficient, and site-selective deoxygenation of primary, secondary, and tertiary alcohols has been realized, under the assistance of a 4-(N-substituted amino)aryl directing group. Only the hydroxyl adjacent to the directing group can be deoxygenated. The deoxygenation is performed in water, with formic acid as both the promoter and hydride donor. Excellent yields and functionality tolerance, as well as high efficiency (S/C up to 1000 000, TOF up to 445 000 h-1), are obtained. The kinetic isotope effect studies show that hydride formation is the rate-determining step, and the deoxygenation follows an SN1-type pathway. The deoxygenation protocol has been demonstrated useful in the structural modification of naturally occurring ketones and steroids.
- Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
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p. 9320 - 9326
(2018/09/21)
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- Chelating Bis(1,2,3-triazol-5-ylidene) Rhodium Complexes: Versatile Catalysts for Hydrosilylation Reactions
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NHC-rhodium complexes (NHC=N-heterocyclic carbenes) have been widely used as efficient catalysts for hydrosilylation reactions. However, the substrates were mostly limited to reactive carbonyl compounds (aldehydes and ketones) or carbon-carbon multiple bonds. Here, we describe the application of newly-developed chelating bis(tzNHC)-rhodium complexes (tz=1,2,3-triazol-5-ylidene) for several reductive transformations. With these catalysts, the formal reductive methylation of amines using carbon dioxide, the hydrosilylation of amides and carboxylic acids, and the reductive alkylation of amines using carboxylic acids have been achieved under mild reaction conditions.
- Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi, Shu
-
supporting information
p. 452 - 458
(2016/02/12)
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- Catalytic N-Alkylation of Amines Using Carboxylic Acids and Molecular Hydrogen
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A convenient, practical and green N-alkylation of amines has been accomplished by applying readily available carboxylic acids in the presence of molecular hydrogen. Applying an in situ formed ruthenium/triphos complex and an organic acid as cocatalyst, a broad range of alkylated secondary and tertiary amines are obtained in good to excellent yields. This novel method is also successfully applied for the synthesis of unsymmetrically substituted N-methyl/alkyl anilines through a direct three-component coupling reaction of the corresponding amines, carboxylic acids, and CO2 as a C1 source.
- Sorribes, Iván,Cabrero-Antonino, Jose R.,Vicent, Cristian,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 13580 - 13587
(2015/11/10)
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- Copper-catalyzed C-N bond cross-coupling of aryl halides and amines in water in the presence of ligand derived from oxalyl dihydrazide: Scope and limitation
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An efficient and convenient method has been developed for the copper-catalyzed C-N bond cross-coupling of aryl bromides with electron-donor substituents and aliphatic amines in water. The new ligand system N-phenyloxalyl bishydrazide/hexane-2,5-dione has been shown to be considerably more efficient in the copper-catalyzed C-N bond cross-coupling reaction as compared to the ligands described in the literature and allowed decreasing of the catalyst amount (up to 2 mol %) to achieve acceptable yields of isolated products (46-84%). Acceptor substituted aryl bromides, aryl bromides with substituents in the ortho-position, and some aryl dichlorides can undergo the C-N cross-coupling under the developed conditions, but their reactivity is lower.
- Kurandina,Eliseenkov,Khaibulova,Petrov,Boyarskiy
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p. 7931 - 7937
(2015/09/15)
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- Iron(III)-catalyzed C-H functionalization: Ortho-benzoyloxylation of N,N-dialkylanilines and its application to 1,4-benzoxazepines
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A C-O bond-formation reaction that proceeds through C-H functionalization of N,N-dialkylanilines at the ortho-position is presented. The iron-catalyzed selective ortho-benzoyloxylation follows a polar Friedel-Crafts-like mechanism and is sensitive to the nucleophilicity of the anilines. The benzoyl-oxylation of a variety of N,N-disubstituted anilines and Nphenyl heterocycles is carried out under extremely mild conditions. Furthermore, the methodology has been successfully employed for the generation of 1,4-benzoxazepines and oaminophenols.
- Chiranjeevi, Barreddi,Vinayak, Botla,Parsharamulu, Thupakula,PhaniBabu, Vemulapalli S.,Jagadeesh, Bharatam,Sridhar, Balasubramanian,Chandrasekharam, Malapaka
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p. 7839 - 7849
(2015/01/16)
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- Ligand-free copper(i) oxide nanoparticle-catalysed amination of aryl halides in ionic liquids
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In the following, we present a simple and feasible methodology for a C-N coupling reaction using nanoscale Cu2O catalysts incorporated in n-Bu4POAc ionic liquid media. It is shown that a wide range of amines and aryl halides can be coupled selectively in high yields, without the use of ligands or additives (bases) and without precautions against water or air. All catalyses can be carried out with a nanoparticle catalyst loading as low as 5 mol%, based on the used precursor.
- Kessler, Michael T.,Robke, Silas,Sahler, Sebastian,Prechtl, Martin H. G.
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p. 102 - 108
(2014/01/06)
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- Direct catalytic N-alkylation of amines with carboxylic acids
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A straightforward process for the N-alkylation of amines has been developed applying readily available carboxylic acids and silanes as the hydride source. Complementary to known reductive aminations, effective C-N bond construction proceeds under mild conditions and allows obtaining a broad range of alkylated secondary and tertiary amines, including fluoroalkyl-substituted anilines as well as the bioactive compound Cinacalcet HCl.
- Sorribes, Iván,Junge, Kathrin,Beller, Matthias
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p. 14314 - 14319
(2014/12/10)
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- Ruthenium-catalyzed N-alkylation of amines with alcohols under mild conditions using the borrowing hydrogen methodology
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Using a simple amino amide ligand, ruthenium-catalyzed one-pot alkylation of primary and secondary amines with simple alcohols was carried out under a wide range of conditions. Using the alcohol as solvent, alkylation was achieved under mild conditions, even as low as room temperature. Reactions occurred with high conversion and selectivity in many cases. Reactions can also be carried out at high temperatures in organic solvent with high selectivity using stoichiometric amounts of the alcohol.
- Enyong, Arrey B.,Moasser, Bahram
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p. 7553 - 7563
(2014/09/17)
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- Homogeneous catalytic hydrogenation of amides to amines
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Hydrogenation of amides in the presence of [Ru(acac)3] (acacH=2,4-pentanedione), triphos [1,1,1-tris- (diphenylphosphinomethyl)ethane] and methanesulfonic acid (MSA) produces secondary and tertiary amines with selectivities as high as 93 % provided that there is at least one aromatic ring on N. The system is also active for the synthesis of primary amines. In an attempt to probe the role of MSA and the mechanism of the reaction, a range of methanesulfonato complexes has been prepared from prepared from [Ru(acac) 3], triphos and MSA, or from reactions of [RuX-(OAc)(triphos)] (X=H or OAc) or [RuH2(CO)(triphos)] with MSA. Crys-tallographically characterised complexes include: [Ru(OAc-κ1O) 2(H2O)-(triphos)], [Ru(OAc-κ2O,O') (CH3SO3-κ1O)(triphos)], [Ru(CH 3SO3-κ1O)2-(H 2O)(triphos)] and [Ru2(μ-CH3SO 3)3-(triphos)2][CH3SO3], whereas other complexes, such as [Ru(OAc-κ1O)(OAc- κ2O,O')(triphos)],[Ru(CH3SO3- κ1O)(CH3SO3-κ2O,O')- (triphos)], H[Ru(CH3SO3-κ1O) 3-(triphos)], [RuH(CH3SO3-κ1O) (CO)-(triphos)] and [RuH(CH3SO3-k2O,O')- (triphos)] have been characterised spectroscopically. The interactions between these various complexes and their relevance to the catalytic reactions are discussed.
- Coetzee, Jacorien,Dodds, Deborah L.,Klankermayer, Jürgen,Brosinski, Sandra,Leitner, Walter,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
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supporting information
p. 11039 - 11050
(2013/09/02)
-
- C(sp3)-F bond activation of CF3-substituted anilines with catalytically generated silicon cations: Spectroscopic evidence for a hydride-bridged Ru-S dimer in the catalytic cycle
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Heterolytic splitting of the Si-H bond mediated by a Ru-S bond forms a sulfur-stabilized silicon cation that is sufficiently electrophilic to abstract fluoride from CF3 groups attached to selected anilines. The ability of the Ru-H complex, generated in the cooperative activation step, to intramolecularly transfer its hydride to the intermediate carbenium ion (stabilized in the form of a cationic thioether complex) is markedly dependent on the electronic nature of its phosphine ligand. An electron-deficient phosphine thwarts the reduction step but, based on the Ru-S catalyst, half of an equivalent of an added alkoxide not only facilitates but also accelerates the catalysis. The intriguing effect is rationalized by the formation of a hydride-bridged Ru-S dimer that was detected by 1H NMR spectroscopy. A refined catalytic cycle is proposed.
- Stahl, Timo,Klare, Hendrik F. T.,Oestreich, Martin
-
supporting information
p. 1248 - 1251
(2013/03/29)
-
- Cu(ii)-catalyzed C-H (SP3) oxidation and C-N cleavage: Base-switched methylenation and formylation using tetramethylethylenediamine as a carbon source
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Base-switched methylenation and formylation using tetramethylethylenediamine (TMEDA) as a carbon source have been achieved under mild conditions, catalyzed by CuCl2, with atmospheric oxygen as oxidant. Bisindolylmethanes, diphenylmethanes and 3-formylindoles were synthesized with excellent regioselectivity and good yield.
- Zhang, Lei,Peng, Chen,Zhao, Dan,Wang, Yue,Fu, Hai-Jian,Shen, Qi,Li, Jian-Xin
-
supporting information; experimental part
p. 5928 - 5930
(2012/07/27)
-
- Selective N-alkylation of amines using nitriles under hydrogenation conditions: Facile synthesis of secondary and tertiary amines
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Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH4OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction.
- Ikawa, Takashi,Fujita, Yuki,Mizusaki, Tomoteru,Betsuin, Sae,Takamatsu, Haruki,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
-
supporting information; experimental part
p. 293 - 304
(2012/02/01)
-
- CuI/DMPAO-catalyzed N-arylation of acyclic secondary amines
-
DMPAO has been found to be a powerful ligand to enable copper-catalyzed coupling of aryl halides with aliphatic acyclic secondary amines take place under relatively mild conditions, and coupling of aryl halides with primary amines and cyclic secondary amines proceeds at low catalyst loading.
- Zhang, Yu,Yang, Xinye,Yao, Qizheng,Ma, Dawei
-
supporting information; experimental part
p. 3056 - 3059
(2012/07/28)
-
- Efficient catalytic aryl amination of bromoarenes using 3-iminophosphine palladium(II) chloride
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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.
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p. 7 - 18,12
(2012/12/12)
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- Reductive monoalkylation of aromatic and aliphatic nitro compounds and the corresponding amines with nitriles
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(Chemical Equation Presented) A simple, selective, rapid, and efficient procedure for the synthesis of secondary amines from the reductive alkylation of either aliphatic or aromatic nitro compounds and the corresponding amines is reported. Ammonium formate is used as the hydrogen source and Pd/C as the hydrogen transfer catalyst. The reaction is carried out at room temperature. The rate differences for the preferential formation of secondary over tertiary products are due to both steric and electronic factors.
- Nacario, Ruel,Kotakonda, Shailaja,Fouchard, David M. D.,Tillekeratne, L. M. Viranga,Hudson, Richard A.
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p. 471 - 474
(2007/10/03)
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- Studies on Pd/imidazolium salt protocols for aminations of aryl bromides and iodides using lithium hexamethyldisilazide (LHMDS)
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The reactions of a range of secondary amines with aryl bromides and iodides have been performed using an in situ protocol involving palladium and imidazolium salts. Many of these reactions proceed at room temperature, providing a mild protocol for aminations of aryl iodides and bromides. Key to the success of this procedure is the use of lithium hexamethyldisilazide (LHMDS) as base.
- Conesa Lerma, Israel,Cawley, Mark J.,Cloke, F. Geoffrey N.,Arentsen, Katherine,Scott, James S.,Pearson, Stuart E.,Hayler, John,Caddick, Stephen
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p. 5841 - 5848
(2007/10/03)
-
- Mixed Phosphite-Phosphine and Phosphinite-Phosphine Palladacyclic Complexes as Highly Active Catalysts for the Amination of Aryl Chlorides
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Tri-tert-butylphosphine adducts of orthopalladated phosphite and phosphinite complexes formed in situ are excellent catalysts for the Buchwald-Hartwig amination of aryl chloride substrates.
- Bedford, Robin B.,Blake, Michael E.
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p. 1107 - 1110
(2007/10/03)
-
- Amination of aryl bromides catalysed by supported palladium
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Palladium particles immobilised onto a metal oxide support or Pd(0), Pd(II) and [Pd(NH3)4]2+ in NaY zeolite have been prepared and characterised. They exhibit a good activity towards the amination of aryl bromides using secondary amines such as piperidine and diethyl amine with a good regio-selectivity for these reactions. Low Pd concentrations (1 mol%) are required to observe a reasonable regio-selectivity. The catalysts can easily be separated from the reaction mixture (filtration) and reused without loss of activity and selectivity. The electronic nature of the aryl halides plays an important role for both the reaction yields and the regio-control of the reaction. It depends on the relation of the direct amination via a benzyne intermediate versus the Pd-catalysed route.
- Djakovitch, Laurent,Wagner, Michael,Koehler, Klaus
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p. 225 - 234
(2007/10/03)
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- Palladium-catalyzed amination of aryl bromides utilizing arene-chromium complexes as ligands
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The arene - chromium complexes of o-diphenylphosphino α- phenylethylamine or α-phenylethyl methyl ether derivatives were examined with regard to their activity as ligands for palladium(0)-catalyzed aryl amination of aryl bromides with a variety of amines. Both steric and electronic factors were found to be significant for the efficient palladium- catalyzed aryl amination reactions. Modulation of the inductive capacity of the arylphosphine atom was achieved by photoinduced ligand exchange of one carbonyl of the chromium tripode in the presence of electron-donating triphenylphosphine or phosphite. Among these arene - chromium ligands, the use of the monophosphineor monophosphite-(dicarbonyl)chromium of N,N- dimethyl α-(o-diphenylphosphino)phenylethylamine and methyl α-(o- diphenylphosphino)phenylethyl ether produced the palladium(0)-catalyzed aryl amination products with cyclic amines or acyclic secondary amines in high yields; the corresponding strong electron-withdrawing tricarbonylchromium complex resulted in a modest yield of the aryl amination.
- Kamikawa, Ken,Sugimoto, Suguru,Uemura, Motokazu
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p. 8407 - 8410
(2007/10/03)
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- Mild and Regiospecific Reduction of Masked 1,3-Dicarbonyl Derivatives to Monocarbonyl Compounds and Primary and Secodary Amines
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The regiospecific reduction of masked 1,3-dicarbonyl compounds to the corresponding saturated monocarbonyl 3 or iminic 4 compounds via 3-amino-2-alkenimines 1 is described.The formation of 3 and 4 can be explained in terms of a double reduction process from 1.A simple method for the synthesis of primary and secondary amines 6 is also described.
- Barluenga, Jose,Aguilar, Enrique,Olano, Bernardo,Fustero, Santos
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p. 1741 - 1744
(2007/10/02)
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- SYNTHESIS OF INDOLES FROM N-ARYL-1-ALKENYLSULPHINAMIDES
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Reactions of 1-alkenylmagnesium bromides with N-sulphinyl-benzenamines affords the title sulphinamides 5.On heating in toluene, these sulphonamides 5 are the transformed into the corresponding indoles.
- Baudin, Jean-Bernard,Julia, Sylvestre A.
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p. 837 - 840
(2007/10/02)
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- Substituted N,N-Dialkylanilines: Relative Ionization Energies and Proton Affinities through Determination of Ion-Molecule Reaction Equilibrium Constants
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The relative ionization energies and proton affinities of N,N-dimethyl-, N,N-diethyl-, and N,N-di-n-propylaniline, and meta- and para-methyl-substituted analogues (as well as N,N,3,5-tetramethylaniline and 4-chloro-N,N-diethylaniline) have been determined in the gas phase through measurements of the equilibrium constants of charge-transfer and proton-transfer reactions in an ion cyclotron resonance spectrometer.Absolute values are assigned to the ionization energies and proton affinities generated in these experiments.Comparison atandards were the ionization potential (7.12 eV) and proton affinity (223.4 kcal/mol) for N,N-dimethylaniline taken from the literature.The heats of formation of the parent radical cations, M+, and the corresponding protonated molecules, MH+, vary in the same way, differing from one another by 21 +/- 2 kcal/mol over the entire set; that is, the radical cations of these compounds display a constant hydrogen affinity of 74 +/- 2 kcal/mol.This is interpreted to mean that all the compounds protonate at the nitrogen atom; previous work had suggested that meta-substituted isomers protonate on the ring.Further, it is demonstrated that variations in both the ionization energy and the proton affinity values upon changes in ring substitution can be predicted from the appropriate Hammett ? values, but not from the corresponding ?+ values; changes brought about by differing N-substituents correlate with ?* values.
- Lias, Sharon G.,Jackson, Jo-Anne A.,Argentar, Harold,Liebman, Joel F.
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p. 333 - 338
(2007/10/02)
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- THE MECHANISM OF N-ALKYLATION OF WEAK N-H-ACIDS BY PHASE TRANSFER CATALYSIS
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The alkylation of aromatic amines in the presence of inorganic bases is accelerated by a PT catalyst even if KHCO3 is the base.ArNR(1-) ions seem not to be involved.A novel type of mechanism for a PTC process is proposed.
- Dehmlow, Eckehard V.,Thieser, Rainer,Zahalka, Hayder Ali,Sasson, Yoel
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p. 297 - 300
(2007/10/02)
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- USE OF HEXAMETHYLPHOSPHORAMIDE (HMPA) IN THE ALKYLATION OF AROMATIC AMINES
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The convenience of using HMPA as solvent in the mono and dialkylation of anilines was demonstrated through the study of the reaction of p-toluidine with alkyl halides, tosylates and epoxides.
- Juaristi, Eusebio,Reyna, J. Daniel
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p. 3521 - 3524
(2007/10/02)
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- PALLADIUM-CATALYZED AROMATIC AMINATION OF ARYL BROMIDES WITH N,N-DIETHYLAMINO-TRIBUTYLTIN
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The reaction of N,N-diethylamino-tributyltin with aryl bromides in the presence of a catalytic amount of PdCl2(o-tolyl3P)2 gave N,N-diethylaminobenzene derivatives.The reaction is a new kind of amination different from ones through aryne or SRN1 mechanism.
- Kosugi, Masanori,Kameyama,Masayuki,Migita, Toshihiko
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p. 927 - 928
(2007/10/02)
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- Photochemical Reactions of Substituted Benzenes with Aliphatic Amines
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The products arising from the irradiation of diethylamine and t-butylamine with toluene, chlorobenzene, anisole, benzonitrile, benzyl fluoride, benzotrifluoride (α,α,α-trifluorotoluene), m-fluorobenzotrifluoride (α,α,α,m-tetrafluorotoluene), p-fluorotoluene, m-fluorotoluene, p-fluoroanisole, m-fluoroanisole, and 1,3-bis(trifluoromethyl)benzene, and of triethylamine with toluene, benzotrifluoride and 1,3-bis(trifluoromethyl)benzene, all at 254 nm, are described.Reaction pathways involving both substitution and 1,2- and 1,4-acyclic addition processes are observed and which predominates depends upon the arene substituent.The novel acyclic adduct, Me2C=CH-CH=CH-CH=NBut, is obtained from toluene and t-butylamine and, contrary to previous reports, chlorobenzene yields arene-amine 1:1 adducts as well as the amine α-substitution product (16); benzonitrile gives aniline derivatives with the primary and secondary amines.
- Gilbert, Andrew,Krestonosich, Stefan,Westover, David L.
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p. 295 - 302
(2007/10/02)
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