- Catalytic Amination of Phenols with Amines
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Given the wide prevalence and ready availability of both phenols and amines, aniline synthesis through direct coupling between these starting materials would be extremely attractive. Herein, we describe a rhodium-catalyzed amination of phenols, which provides concise access to diverse anilines, with water as the sole byproduct. The arenophilic rhodium catalyst facilitates the inherently difficult keto–enol tautomerization of phenols by means of π-coordination, allowing for the subsequent dehydrative condensation with amines. We demonstrate the generality of this redox-neutral catalysis by carrying out reactions of a large array of phenols with various electronic properties and a wide variety of primary and secondary amines. Several examples of late-stage functionalization of structurally complex bioactive molecules, including pharmaceuticals, further illustrate the potential broad utility of the method.
- Chen, Kai,Kang, Qi-Kai,Li, Yuntong,Wu, Wen-Qiang,Zhu, Hui,Shi, Hang
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supporting information
p. 1144 - 1151
(2022/02/05)
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- Synthesis of secondary amines by reductive amination of aldehydes with nitroarenes over supported copper catalysts in a flow reactor
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Supported copper catalysts were investigated for the one-pot reductive amination of aldehydes with nitroarenes in a continuous flow reactor. This process is considered advantageous compared to current traditional methods, which present several drawbacks, such as toxicity of reducing or alkylation agent, lack of monoalkylation selectivity and large amounts of waste produced. Various secondary amines were synthesized in good to excellent yields in the reactions of aliphatic aldehydes with nitroarenes using molecular hydrogen as a reducing agent. It was found that the yield of secondary amine depends on the rate of formation of intermediate imine.
- Nuzhdin, Alexey L.,Artiukha, Ekaterina A.,Bukhtiyarova, Galina A.,Derevyannikova, Elizaveta A.,Bukhtiyarov, Valerii I.
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p. 108 - 113
(2017/09/15)
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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
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supporting information
p. 452 - 458
(2016/02/12)
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- Development of a general non-noble metal catalyst for the benign amination of alcohols with amines and ammonia
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The N-alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N-alkyl amines. However, as a potentially clean and economic choice for N-alkyl amine synthesis, non-noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N-alkylation of ammonia or amines with alcohol or primary amines. N-alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N-heterocyclic compounds, and secondary amines could be N-alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one-pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation. Copyright
- Cui, Xinjiang,Dai, Xingchao,Deng, Youquan,Shi, Feng
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supporting information
p. 3665 - 3675
(2013/03/29)
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- Palladium-catalyzed aerobic dehydrogenative aromatization of cyclohexanone imines to arylamines
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Dehydrogenative aromatization of cyclohexanone imines to arylamines has been achieved using a palladium catalyst under aerobic conditions. The reaction is applicable to a variety of imines that are either preformed or generated in situ from cyclohexanone derivatives and aryl or alkylamines.
- Hajra, Alakananda,Wei, Ye,Yoshikai, Naohiko
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supporting information
p. 5488 - 5491,4
(2012/12/12)
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- Au/Ag-Mo nano-rods catalyzed reductive coupling of nitrobenzenes and alcohols using glycerol as the hydrogen source
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A highly efficient Au/Ag-Mo nano-rods catalyst was prepared for the one-pot synthesis of imine and amine using equal molar ratio of nitrobenzene and alcohol as starting materials, and bio-based glycerol as the hydrogen source. The reaction mechanism of the nitrobenzene reduction, amine and aldehyde coupling, and imine reduction was explored.
- Cui, Xinjiang,Zhang, Chengming,Shi, Feng,Deng, Youquan
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supporting information; experimental part
p. 9391 - 9393
(2012/09/21)
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- C-N bond formation catalysed by CuI Bonded to polyaniline nanofiber
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Polyaniline nanofiber as a macroligand for the supported cuprous iodide catalyst (CuI-PANInf) has been developed for the coupling of aryl halides (including aryl chlorides) with aliphatic, aromatic, and N(H)-heterocyclic amines under ambient conditions (80 °C for aryl chlorides) has been developed. This simple and efficient method for coupling reactions is highly versatile, convenient, and also the catalyst can be used for several cycles with good-to-excellent yields.
- Arundhathi, Racha,Kumar, Desitti Chaitanya,Sreedhar, Bojja
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supporting information; experimental part
p. 3621 - 3630
(2010/08/20)
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- Highly selective N-Alkylation of amines promoted on silica: An efficient and recyclable surface
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N-Alkylation of amines suffers from competing over alkylations. At the same time, use of strong base and other harsh conditions greatly limits providing a practical, generalized and selective procedure. Activated silica gel has been found to promote N-alkylations of amines. Here, we studied N-alkylation of amines with various types of alkyl halides, which finally constitute practical, highly selective and eco-friendly conditions for mono- or bis-alkylated amines at ambient temperature with recyclability of silica.
- Basu, Basudeb,Paul, Susmita,Nanda, Ashis K.
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experimental part
p. 1115 - 1120
(2010/05/02)
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- Iron/copper-cocatalyzed ullmann N,O-arylation using FeCl3, CuO, and rac-1,1′-Binaphthyl-2,2′-diol
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We have developed an efficient and inexpensive bimetallic catalyst FeCl3, CuO, and rac-BINOL that could promote N,O-arylation of aliphatic, arylamines, and phenols. The cross-coupling reaction conditions have high tolerance of various functional groups. This versatile and efficient iron/copper-cocatalyst can widely be used in the synthesis of the compounds containing (aryl)C-N or (aryl)C-O(aryl) bond. Georg Thieme Verlag Stuttgart.
- Wang, Zhe,Fu, Hua,Jiang, Yuyang,Zhao, Yufen
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body text
p. 2540 - 2546
(2009/04/12)
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- A mild and efficient method for copper-catalyzed Ullmann-type N-arylation of aliphatic amines and amino acids
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An efficient and general protocol for copper-catalyzed N-arylation of aliphatic amines and amino acids has been developed using aryl iodides under mild conditions (coupling temperature at 25-35°C). For the N-(o-nitrophenyl) amino acid derivatives, subsequent reduction of the nitro group in the presence of tin(II) chloride resulted in 3,4-dihydroquinoxalin-2(1H)-one derivatives in good yields. Georg Thieme Verlag Stuttgart New York.
- Jiang, Qun,Jiang, Deshou,Jiang, Yuyang,Fu, Hua,Zhao, Yufen
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p. 1836 - 1842
(2008/02/10)
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- Titanium and zirconium complexes with helical bis(phenolato) ligands as hydroamination catalysts
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A racemic bisphenolato (OSSO)-type ligand that contains a trans-1,2-cyclohexanediyl backbone can be obtained in two steps from commercially available starting materials. In situ combination of this ligand with Ti(NMe2)4 or Zr(NMesub
- Marcseková, Klaudia,Loos, Christian,Rominger, Frank,Doye, Sven
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p. 2564 - 2568
(2008/02/13)
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- [Ind2TiMe2]: A general catalyst for the intermolecular hydroamination of alkynes
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[Ind2TiMe2] (Ind=indenyl) is a highly active and general catalyst for the intermolecular hydroamination of alkynes. It catalyzes the reaction of primary aryl-, tert-alkyl-, sec-alkyl-, and nalkylamines with internal and terminal alkynes. In the case of unsymmetrically substituted 1-phenyl-2-alkylalkynes, the reactions occur with modest to excellent regioselectivities, whereby formation of the anti-Markovnikov regioisomers is favored. While the major product of hydroamination reactions of terminal arylalkynes is always the anti-Markovnikov isomer, alkylalkynes react with arylamines to preferably give the Markovnikov products. To achieve reasonable rates for the addition of sterically less hindered n-alkyland benzylamines to alkynes, these amines must be added slowly to the reaction mixtures. This behavior is explained by the fact that the catalytic cycle proposed on the basis of an initial kinetic investigation includes the possibility that the rate of the reaction increases with decreasing concentration of the employed amine. Furthermore, no dimerization of the catalytically active imido complex is observed in the hydroamination of 1-phenylpropyne with 4-methylaniline in the presence of [Ind2TiMe2] as catalyst. In general, a combination of [Ind2TiMe2]-catalyzed hydroamination of alkynes with subsequent reduction leads to the formation of secondary amines with good to excellent yields. Particularly impressive is that [Ind 2TiMe2] makes it possible for the first time to perform the reactions of n-alkyl- and benzylamines with 1-phenylpropyne in a highly regioselective fashion.
- Heutling, Andreas,Pohlki, Frauke,Doye, Sven
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p. 3059 - 3071
(2007/10/03)
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- Microwave-assisted catalytic intermolecular hydroamination of alkynes
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Irradiation of reaction mixtures containing an alkyne, an amine, and a catalytic amount of Cp2TiMe2 in toluene with microwaves at a frequency of 2.45 GHz and a power output of 180-300 W results in fast reactions to give the corresponding hydroamination products. The initially formed imines can easily be reduced to secondary amines by use of H2/Pd, LiAlH4, or NaCNBH3/p-TsOH. The microwave-assisted hydroamination reactions go to completion within one tenth (or less) of the time required for reactions run conventionally in an oil bath at 105 °C. By using the microwave technology, it is possible to achieve turnover frequencies TOF > 10 h-1. Furthermore, when Cp2TiMe2 is used as the catalyst, hydroamination products of terminal alkynes can be isolated in reasonable yields for the first time. The addition of amines to terminal alkynes gives access to both the Markovnikov and the anti-Markovnikov products. Observed regioselectivities are different for terminal aryl- and alkylalkynes.
- Bytschkov, Igor,Doye, Sven
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p. 4411 - 4418
(2007/10/03)
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