- Transition Metal-Free Synthesis of meta-Bromo- and meta-Trifluoromethylanilines from Cyclopentanones by a Cascade Reaction
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Anilines are key constituents in biologically active compounds and often obtained from transition metal-catalyzed coupling of an aryl halide with an amine. In this work, we report a transition metal-free method for the synthesis of meta-bromo- and meta-trifluoromethylanilines starting from 3-tribromomethylcyclopentanone or 3-(2-bromo-2-chloro-1,1,1-trifluoroethyl)cyclopentanone, respectively. The scope of the transformation is shown by application of primary, secondary and aromatic amines. The reaction proceeds in acceptable to high yields (20–81 %), and allows for the synthesis of anilines with substitution patterns otherwise difficult to access.
- Bunch, Lennart,Cetin, Adnan,Staudt, Markus
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supporting information
(2022/02/10)
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- Convenient and Reusable Manganese-Based Nanocatalyst for Amination of Alcohols
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The development of new sustainable nanocatalytic systems for green chemical synthesis is a growing area in chemical science. Herein, a reusable heterogeneous N-doped graphene-based manganese nanocatalyst (Mn@NrGO) for selective N-alkylation of amines with alcohols is described. Mechanistic studies illustrate that the catalytic reaction follows a domino dehydrogenation-condensation-hydrogenation sequence of alcohols and amines with the formation of water as the sole by-product. The scope of the reaction is extended to the synthesis of pharmaceutically important N-alkylated amine intermediates. The heterogeneous nature of the catalyst made it easy to separate for long-term performance, and the recycling study revealed that the catalyst was robust and retained its activity after several recycling experiments.
- Subaramanian, Murugan,Ramar, Palmurukan M.,Sivakumar, Ganesan,Kadam, Ravishankar G.,Petr, Martin,Zboril, Radek,Gawande, Manoj B.,Balaraman, Ekambaram
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p. 4334 - 4341
(2021/08/25)
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- Half-sandwich Ru(ii) arene complexes bearing benzimidazole ligands for theN-alkylation reaction of aniline with alcohols in a solvent-free medium
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In this article, the directN-alkylation reactions of amines with alcohol derivatives using the borrowing hydrogen methodology have been investigated. For this purpose, a new series of half-sandwich ruthenium(ii) complexes bearing N-coordinated benzimidazole complexes have been synthesized and fully characterized by FT-IR,1H NMR and13C NMR spectroscopies. Additionally, the structures of the complexes2a-2ehave been characterized by X-ray crystallography. All new complexes were investigated for their catalytic activities in the alkylation reaction of amines with alcohol derivatives. It was found that alkylation reactions in a solvent-free medium are efficient and selective.
- ?i?ek, Metin,Gürbüz, Nevin,?zdemir, Nam?k,?zdemir, ?smail,?spir, Esin
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p. 11075 - 11085
(2021/07/02)
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- Zinc-Catalyzed N-Alkylation of Aromatic Amines with Alcohols: A Ligand-Free Approach
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An efficient zinc-catalyzed N-alkylation reaction of aromatic amines was achieved using aliphatic, aromatic, and heteroaromatic alcohols as the alkylating reagent. A variety of aniline derivatives, including heteroaromatic amines, underwent the N-alkylation reaction and furnished the corresponding monoalkylated products in good to excellent yields. The application of the reaction is also further demonstrated by the synthesis of a 2-phenylquinoline derivative from acetophenone and 2-aminobenzyl alcohol. Deuterium labeling experiments show that the reaction proceeds via a borrowing hydrogen process. (Figure presented.).
- Sankar, Velayudham,Kathiresan, Murugavel,Sivakumar, Bitragunta,Mannathan, Subramaniyan
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supporting information
p. 4409 - 4414
(2020/09/01)
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- Borrowing Hydrogen-Mediated N-Alkylation Reactions by a Well-Defined Homogeneous Nickel Catalyst
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We report herein a well-defined and bench-stable azo-phenolate ligand-coordinated nickel catalyst which can efficiently execute N-alkylation of a variety of anilines by alcohol. We demonstrate that the redox-active azo ligand can store hydrogen generated during alcohol oxidation and redelivers the same to an in-situ-generated imine bond to result in N-alkylation of amines. The reaction has wide scope, and a large array of alcohols can directly couple to a variety of anilines. Mechanistic studies including deuterium labeling to the substrate establishes the borrowing hydrogen method from alcohols and pinpoints the crucial role of the redox-active azo moiety present on the ligand backbone. Isolation of the ketyl intermediate in its trapped form with a radical quencher and higher kH/kD for the alcohol oxidation step suggest altogether a hydrogen-atom transfer (HAT) to the reduced azo backbone to pave alcohol oxidation as opposed to the conventional metal-ligand bifunctional mechanism. This example clearly demonstrates that an inexpensive base metal catalyst can accomplish an important coupling reaction with the help of a redox-active ligand backbone.
- Bains, Amreen K.,Kundu, Abhishek,Yadav, Sudha,Adhikari, Debashis
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p. 9051 - 9059
(2019/10/02)
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- A microwave-assisted SmI2-catalyzed direct N-alkylation of anilines with alcohols
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A new protocol for the alkylation of aromatic amines has been described using alcohols in the presence of SmI2 as a catalyst with the generation of water as the sole byproduct. The reaction proceeds under MW conditions and selectively generates monoalkylated amines. This protocol features a broad substrate scope and good functional-group tolerance with moderate to high yields.
- Gour, Jitendra,Gatadi, Srikanth,Malasala, Satyaveni,Yaddanpudi, Madhavi Venkata,Nanduri, Srinivas
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p. 7488 - 7494
(2019/06/14)
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- Phosphorous(v) Lewis acids: Water/base tolerant P3-trimethylated trications
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The water/base intolerance of the previously reported electrophilic phosphonium cations has been overcome by replacing the labile electron-withdrawing groups generally attached to phosphorus (e.g. -F, -OAr, -CF3) with methyl groups. Tri-phosphorus(v) tricationic species, accessible in one-pot from commercially available materials, are air and water/base tolerant, yet are sufficiently Lewis acidic for catalysis.
- Bayne,Fasano,Szkop,Ingleson,Stephan
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supporting information
p. 12467 - 12470
(2018/11/20)
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- Direct access to: N -alkylated amines and imines via acceptorless dehydrogenative coupling catalyzed by a cobalt(ii)-NNN pincer complex
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A simple, phosphine-free Co(ii)-NNN pincer complex catalyzed direct N-alkylation of anilines with alcohols via hydrogen auto-transfer (HA) and selective acceptorless dehydrogenative coupling (ADC) of benzylamines with alcohols affording imines with the liberation of molecular hydrogen and water is reported.
- Midya, Siba P.,Pitchaimani, Jayaraman,Landge, Vinod G.,Madhu, Vedichi,Balaraman, Ekambaram
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p. 3469 - 3473
(2018/07/29)
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- Manganese catalyzed N-alkylation of anilines with alcohols: Ligand enabled selectivity
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Ligand enabled Earth-abundant manganese catalyzed N-alkylation of amines with alcohols via a hydrogen auto-transfer strategy is reported. The choice of the ligand plays a significant role in the alcohol reactivity (aliphatic or aromatic) toward N-alkylation reactions.
- Landge, Vinod G.,Mondal, Akash,Kumar, Vinit,Nandakumar, Avanashiappn,Balaraman, Ekambaram
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supporting information
p. 8175 - 8180
(2018/11/23)
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- An Efficient Homogenized Ruthenium(II) Pincer Complex for N-Monoalkylation of Amines with Alcohols
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An ionic 2,6-bis(imidazo[1,2-α]pyridin-2-yl)pyridine-based N^N^N pincer ruthenium(II) complex exhibited high efficiency in the C–N bond formation between amines and alcohols by the “borrowing hydrogen” (BH) or “hydrogen autotransfer” (HA) concept. The synthetic protocol selectively generated monoalkylated amines without formation of tertiary amines during the reaction. The unique selectivity enabled the formation of symmetrically and asymmetrically substituted diamines. This methodology features several advantages including a low catalyst loading (as low as 0.5 mol-%), a short reaction time (as short as 2 h), and excellent N-monoalkylation selectivity.
- Yang, Fa-Liu,Wang, Ying-Hui,Ni, Yong-Feng,Gao, Xiang,Song, Bing,Zhu, Xinju,Hao, Xin-Qi
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p. 3481 - 3486
(2017/07/04)
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- An Efficient and Selective Nickel-Catalyzed Direct N-Alkylation of Anilines with Alcohols
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Herein, we developed an efficient and selective nickel-catalyzed monoalkylation of various primary alcohols with aryl and heteroaryl amines together with diols and amino alcohol derivatives. Notably, the catalytic protocol consisting of an earth-abundant and non-precious NiBr2/L1 system enables the transformations in the presence of hydroxyl, alkene, nitrile, and nitro functionalities. As a highlight, we have demonstrated the alkylation of diamine, intramolecular cyclization to N-heterocycles, and functionalization of complex vitamin E, an (±)-α-tocopherol derivative. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.
- Vellakkaran, Mari,Singh, Khushboo,Banerjee, Debasis
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p. 8152 - 8158
(2017/12/08)
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- Discovery of N-(Naphthalen-1-yl)-N′-alkyl Oxalamide Ligands Enables Cu-Catalyzed Aryl Amination with High Turnovers
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A class of N-(naphthalen-1-yl)-N′-alkyl oxalamides have been proven to be powerful ligands, making a coupling reaction of (hetero)aryl iodides with primary amines proceed at 50 °C with only 0.01 mol % of Cu2O and ligand as well as a coupling reaction of (hetero)aryl bromides with primary amines and ammonia at 80 °C with only 0.1 mol % of Cu2O and ligand. A wide range of coupling partners work well under these conditions, thereby providing an easy to operate method for preparing (hetero)aryl amines.
- Gao, Jie,Bhunia, Subhajit,Wang, Kailiang,Gan, Lu,Xia, Shanghua,Ma, Dawei
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supporting information
p. 2809 - 2812
(2017/06/07)
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- CuI/Oxalic Diamide Catalyzed Coupling Reaction of (Hetero)Aryl Chlorides and Amines
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A class of oxalic diamides are found to be effective ligands for promoting CuI-catalyzed aryl amination with less reactive (hetero)aryl chlorides. The reaction proceeds at 120 °C with K3PO4 as the base in DMSO to afford a wide range of (hetero)aryl amines in good to excellent yields. The bis(N-aryl) substituted oxalamides are superior ligands to N-aryl-N′-alkyl substituted or bis(N-alkyl) substituted oxalamides. Both the electronic nature and the steric property of the aromatic rings in ligands are important for their efficiency.
- Zhou, Wei,Fan, Mengyang,Yin, Junli,Jiang, Yongwen,Ma, Dawei
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supporting information
p. 11942 - 11945
(2015/10/06)
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- Insight into O2-promoted base-catalyzed N-alkylation of amines with alcohols
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A highly efficient and practical transition-metal-free CsOH/O2 catalyst system was developed for the N-alkylation of amines with alcohols under argon. This strategy was compatible with many alcohols and exhibits excellent functional group tolerance. More significantly, the selective formation of secondary amines was achieved in excellent yields. The detailed mechanistic study gave a clear understanding of the role of base and oxygen in the catalytic cycle.
- Wang, Chao,Chen, Changpeng,Han, Jian,Zhang, Jingyu,Yao, Yingming,Zhao, Yingsheng
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supporting information
p. 2972 - 2977
(2015/04/27)
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- New ligands for copper-catalyzed C-N coupling reactions at gentle temperature
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Pyridin-2-ol-N-oxide was designed as an efficient ligand for the coupling reaction of aryl iodides, aryl bromides and aryl chlorides, respectively, with primary amines, cyclic secondary amines or N-containing heterocycles at room or moderate temperature. The catalytic system showed great functional groups tolerance and excellent selective reactivity.
- Su, Jinyue,Qiu, Yatao,Jiang, Sheng,Zhang, Dayong
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supporting information
p. 685 - 688
(2014/10/15)
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- 3D-printed devices for continuous-flow organic chemistry
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We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products.
- Dragone, Vincenza,Sans, Victor,Rosnes, Mali H.,Kitson, Philip J.,Cronin, Leroy
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supporting information
p. 951 - 959
(2013/06/27)
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- Room temperature and solvent-free iridium-catalyzed selective alkylation of anilines with alcohols
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A bidentate iridium NHC-phosphine complex has been developed and applied to the N-monoalkylation of aromatic amines with a wide range of primary alcohols and to the N-heterocyclization of amino alcohols. This reaction resulted in high isolated product yields, even at room temperature and under solvent-free conditions. The Royal Society of Chemistry 2013.
- Li, Jia-Qi,Andersson, Pher G.
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supporting information
p. 6131 - 6133
(2013/07/26)
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- S-Benzyl isothiouronium chloride as a recoverable organocatalyst for the direct reductive amination of aldehydes
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The direct reductive amination of aldehydes using S-benzyl isothiouronium chloride as a recoverable organocatalyst for the activation of the imine intermediate through hydrogen bonding is described. A mild and operationally simple fragment coupling procedure was accomplished with a wide range of aldehydes as well as amines in good to excellent yields. In addition, the S-benzyl isothiouronium chloride catalyst was easily recovered by simple filtration and reused without any drop in its efficiency.
- Nguyen, Quynh Pham Bao,Kim, Taek Hyeon
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supporting information; experimental part
p. 5004 - 5007
(2011/10/07)
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- Iron/amino acid catalyzed direct N-alkylation of amines with alcohols
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(Chemical Equation Presented) Ironing it out: The straightforward N-alkylation using alcohols and iron/amino acid catalysis is described (see scheme). The reaction does not proceed by the conventional "borrowing hydrogen" mechanism, but appears to involve a substitution pathway (S N) at the sp3 carbon atom bearing the hydroxy group of the alcohol. Developing a catalyst that is effective at a near neutral pH was key to the successful N-alkylation.
- Zhao, Yingsheng,Foo, Siong Wan,Saito, Susumu
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supporting information; experimental part
p. 3006 - 3009
(2011/05/04)
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- Selective N-alkylation of amines with alcohols by using non-metal-based acid-base cooperative catalysis
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Learning to cooperate: A straightforward method for the selective N-mono- and dialkylation of amines with alcohols by means of non-metal-based catalysis promoted by TAPC is reported (see scheme). Selectivity of the N-mono- and dialkylation, substrate scope and functional-group tolerance are highlighted with respect to each amine (1° and 2°; aromatic and aliphatic) and alcohol (1°, 2° and 3°; benzylic and aliphatic) component. Copyright
- Du, Ya,Oishi, Shunsuke,Saito, Susumu
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supporting information; experimental part
p. 12262 - 12267
(2011/11/29)
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- Efficient ligand-free copper-catalyzed arylation of aliphatic amines
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An efficient and practical protocol has been developed for the cross-coupling of alkyl amines and aryl iodides under ligand-free copper(I) iodide catalyzed conditions. A variety of alkyl amines undergo the catalytic system to afford the N-arylated products in moderate to good yields (up to 93%).
- Yong, Fui-Fong,Teo, Yong-Chua
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experimental part
p. 3068 - 3072
(2011/02/25)
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- Direct reductive amination of carbonyl compounds with primary/secondary amines using recyclable water-soluble FeII/EDTA complex as catalyst
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Direct reductive amination of aliphatic, aromatic and heterocyclic carbonyl compounds with primary/secondary amines is reported with water-soluble FeII/EDTA complex as a catalyst using low-pressure molecular hydrogen in a biphasic media. The catalyst is highly selective, recyclable and is an excellent replacement for expensive noble metal catalysts or stoichiometric reducing agents.
- Bhor, Malhari D.,Bhanushali, Mayur J.,Nandurkar, Nitin S.,Bhanage, Bhalchandra M.
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p. 965 - 969
(2008/09/17)
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- Mild and efficient copper-catalyzed N-arylation of alkylamines and N-H heterocycles using an oxime-phosphine oxide ligand
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A mild and efficient copper-catalyzed system for N-arylation of alkylamines and N-H heterocycles with aryl iodides using a novel, readily prepared and highly stable oxime-functionalized phosphine oxide ligand was developed. The coupling reactions could even be performed in solvent-free conditions with moderate to good yields.
- Xu, Lei,Zhu, Di,Wu, Fan,Wang, Rongliang,Wan, Boshun
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p. 6553 - 6560
(2007/10/03)
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- Copper-catalyzed coupling of alkylamines and aryl iodides: an efficient system even in an air atmosphere.
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[reaction: see text] A mild method for the copper-catalyzed amination of aryl iodides is reported. This operationally simple C-N bond-forming protocol uses CuI as the catalyst and ethylene glycol as ligand in 2-propanol. A variety of functionalized aryl iodides as well as several amines were efficiently coupled using this method. This catalytic amination procedure is relatively insensitive to moisture and can be performed under an air atmosphere with comparable yield. Preliminary results on the amination of aryl bromides are also described.
- Kwong, Fuk Yee,Klapars, Artis,Buchwald, Stephen L
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p. 581 - 584
(2007/10/03)
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