- Acid-catalyzed ortho-alkylation of anilines with styrenes: An improved route to chiral anilines with bulky substituents
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(Chemical Equation Presented) Reaction of para-substituted anilines with styrene derivatives at elevated temperatures, when catalyzed by CF 3SO3H, results in highly chemoselective ortho-alkylation of the aniline. When R = H, dialkylation can be achieved by varying the ratio of styrene to aniline. Several different substituted anilines and styrenes were examined, and good yields (42-87%) were obtained, except in the case where electron-withdrawing substituents are present on the styrene.
- Cherian, Anna E.,Domski, Gregory J.,Rose, Jeffrey M.,Lobkovsky, Emil B.,Coates, Geoffrey W.
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- Iodine-mediated 1,2-aryl migration of primary benzhydryl amines
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An iodine-mediated 1,2-aryl migration reaction of primary benzhydryl amines under transition metal-free conditions has been achieved. The crude imines generated by this rearrangement reaction can be directly transformed into various aromatic secondary ami
- Chang, Junbiao,Du, Yangxu,Hao, Wei,Hou, Jiao,Lu, Qing,Yu, Wenquan
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supporting information
p. 16223 - 16226
(2021/09/22)
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- Chan-Lam Amination of Secondary and Tertiary Benzylic Boronic Esters
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We report a Chan-Lam coupling reaction of benzylic and allylic boronic esters with primary and secondary anilines to form valuable alkyl amine products. Both secondary and tertiary boronic esters can be used as coupling partners, with mono-alkylation of the aniline occurring selectively. This is a rare example of a transition-metal-mediated transformation of a tertiary alkylboron reagent. Initial investigation into the reaction mechanism suggests that transmetalation from B to Cu occurs through a single-electron, rather than a two-electron process.
- Dennis, Francesca M.,Grayson, James D.,Partridge, Benjamin M.,Robertson, Craig C.
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p. 9883 - 9897
(2021/07/20)
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- Chiral N-heterocyclic carbene-iridium complexes for asymmetric reduction of prochiral ketimines
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Enantioselective reduction of imines to the corresponding chiral secondary amines has been studied using a series of chiral half-sandwich iridium complexes. Chiral N-heterocyclic carbene (NHC) ligands in these complexes were synthesized from readily available, naturally occurring amino acids. Inexpensive phenylsilane was used as a convenient hydrogen donor. Under the optimized conditions, Ir-NHC complexes could reduce ketimines in good yields, albeit with moderate enantiomeric excess (ee). The phenylglycine derived chiral NHC was shown to give the best Ir catalyst and it also gave the maximum ee compared to catalysts prepared from other NHCs in this series. The opposite enantiomer of the reduction product was always obtained while using the Ir complex bearing a valine based NHC. The yields were consistently high with a variety of imine substrates having different steric and electronic demands.
- Kathuria, Lakshay,Samuelson, Ashoka G.
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- Iron-Catalyzed Oxidative Amination of Benzylic C(sp3)–H Bonds with Anilines
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Iron-catalyzed oxidative amination of benzylic C(sp3)–H bonds with anilines bearing electron-withdrawing groups (EWGs) or electron-donating groups (EDGs) is realized based on simple variations of N-substituents on imidazolium cations in novel ionic Fe(III) complexes. The structural modification of the imidazolium cation resulted in regulation of the redox potential and the catalytic performance of the iron metal center. Using DTBP as oxidant, [HItBu][FeBr4] showed the highest catalytic activity for anilines bearing EWGs, while [HIPym][FeBr4] was more efficient for EDG-substituted anilines. This work provides alternative access to benzylamines with the advantages of both a wide substrate scope and iron catalysis.
- Song, Yan-Ling,Li, Bei,Xie, Zhen-Biao,Wang, Dan,Sun, Hong-Mei
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p. 17975 - 17985
(2021/12/13)
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- A Tetraarylpyrrole-Based Phosphine Ligand for the Palladium-Catalyzed Amination of Aryl Chlorides
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A tetraarylpyrrole-based phosphine ligand L1 in combination with Pd(dba)2 provided a catalyst for the Buchwald-Hartwig amination reaction. A variety of amines were rapidly coupled with aryl chlorides at a Pd loading of 0.5 mol%. The selective monoarylation of aliphatic primary amines was achieved in the presence of 0.8 equiv. water. Comparison experiments were also conducted, which revealed that the catalytic activity of L1 is superior to representative phosphine ligands in the Pd-catalyzed C?N coupling of various amines. (Figure presented.).
- Sai, Masahiro
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supporting information
p. 5422 - 5428
(2021/10/08)
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- Palladium supported on magnesium hydroxyl fluoride: An effective acid catalyst for the hydrogenation of imines and N-heterocycles
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Palladium catalysts supported on acidic fluorinated magnesium hydroxide Pd/MgF2-x(OH)x were prepared through precipitation or impregnation methods. Applications to the hydrogenation of various aldimines and ketimines resulted in good catalytic activities at mild temperatures using one atmosphere of hydrogen. Quinolines, pyridines and other N-heterocycles were successfully hydrogenated at higher temperature and hydrogen pressure using low palladium loadings and without the use of any acid additive. Such reactivity trend confirmed the positive effect of the Br?nsted and Lewis acid sites from the fluorinated magnesium hydroxide support resulting in the effective pre-activation of N-heterocycle substrates and therefore in the good catalytic activity of the palladium nanoparticles during the hydrogenations. As demonstrated in the hydrogenation of imines, the catalyst was recycled up to 10 times without either loss of activity or palladium leaching. This journal is
- Agbossou-Niedercorn, Francine,Corre, Yann,Dongare, Mohan K.,Kemnitz, Erhard,Kokane, Reshma,Michon, Christophe,Umbarkar, Shubhangi B.
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supporting information
p. 19572 - 19583
(2021/11/04)
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- Preparation of alkylated compounds using the trialkylphosphate
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[Problem] trialkylphosphate strong base used reaction agent, a carboxylic acid, a ketone, an aldehyde, amine, amide, thiol, ester or Grignard reagent to a variety of substrates, and/or high efficiency to generate a highly stereoselective alkylation reaction, the alkylated compounds capable of producing new means. [Solution] was used as the alkylating agent in the alkylation of compound trialkylphosphate, strongly basic reaction production use. [Drawing] no
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Paragraph 0173-0174; 0180
(2021/11/02)
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- Dehydrogenation and α-functionalization of secondary amines by visible-light-mediated catalysis
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A visible-light-mediated process for dehydrogenation of amines has been described. The given protocol showed a broad substrate scope, mild reaction conditions and excellent results without the requirement of tedious purification. This process can be applied in one-pot functionalization of secondary amines with various nucleophiles through the cooperation of visible-light and Lewis acid catalysis, leading to the structurally varied essential components of biologically active molecules. In addition, Stern-Volmer studies and quenching experiments revealed the role of a catalyst and led to the proposed mechanism of this transformation.
- Bujok, Robert,Morawska, Paulina,Pawlowski, Robert,Stanek, Filip,Stodulski, Maciej
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supporting information
p. 2103 - 2112
(2020/03/27)
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- Ruthenium N-Heterocyclic Carbene Complexes for Chemoselective Reduction of Imines and Reductive Amination of Aldehydes and Ketones
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Chemoselective reduction of imines to secondary amines is catalyzed efficiently by tethered and untethered, half-sandwich ruthenium N-heterocyclic carbene (NHC) complexes at room temperature. The untethered Ru-NHC complexes are more efficient as catalysts for the reduction of aldimines and ketimines than the tethered complexes. Using the best untethered complex as a catalyst, electronic and steric demands on the reaction was probed using a series of imines. Chemoselectivity of the catalyst towards imine reduction was tested by performing inter and intramolecular competitive reactions in a variety of ways. The catalyst exhibits a very high TON and TOF under anaerobic conditions.
- Kathuria, Lakshay,Samuelson, Ashoka G.
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supporting information
(2020/06/17)
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- Half-Sandwich Ru(II) Complexes with N,O-Chelate Ligands: Diverse Catalytic Activity for Amine Synthesis in Water
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Several types of β-ketoamino based N,O-coordinate half-sandwich ruthenium complexes have been synthesized in moderate to good yields. The stable ruthenium complexes displayed good and diverse catalytic efficiency in reductive amination between aldehydes and amines in aqueous solution. The method gave a facile route for one-pot synthesis of diverse complicated amines with a low catalyst loading by using cheap and less-toxic HCOOH or clean H2 as hydrogen source. Catalyst Ru1 showed the highest catalytic activity of 190 h-1 TOF value in the reductive amination reaction of benzaldehyde with aniline. The corresponding amine products were furnished in excellent yields under the standard catalysis system. The efficient and diverse catalytic activity, broad substance scope, mild conditions, and environmentally benign solvent made this system potentially applicable in industrial production. Ruthenium complexes were characterized using NMR, elemental analysis, and IR techniques to confirm their structure.
- Yun, Xue-Jing,Ling, Chun,Deng, Wei,Liu, Zhen-Jiang,Yao, Zi-Jian
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p. 3830 - 3838
(2020/11/13)
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- Iron-catalyzed reductive coupling of nitroarenes with olefins: Intermediate of iron-nitroso complex
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Using a single half-sandwich iron(II) compound, CpFe(1,2-Ph2PC6H4S)(NCMe) (Cp- = C5Me5-, 1) as a catalyst, reductive coupling of nitroarenes with olefins has been achieved by a well-defined iron(II)/(EtO)3SiH system. Through either inter- or intramolecular reductive coupling, various branched amines and indole derivatives have been directly synthesized in one-pot. Mechanistic studies showed that the catalysis is initiated by activation of nitroarenes by the iron(II) catalyst with silane, generating iron-nitrosoarene intermediate for the C-N bond coupling.
- Song, Heng,Yang, Zhuoyi,Tung, Chen-Ho,Wang, Wenguang
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p. 276 - 281
(2019/12/24)
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- In Water Markovnikov Hydration and One-Pot Reductive Hydroamination of Terminal Alkynes under Ruthenium Nanoparticle Catalysis
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In the presence of Shvo's catalyst [2,3,4,5-tetraphenyl-1,3-cyclopentadien-1-ol, ruthenium(II) complex], a small quantity of aniline and TGPS-750-M surfactant, terminal alkynes were hydrated under microwave (MW) dielectric heating in water as solvent with high conversion and good yield. The reaction gives the Markovnikov product exclusively, unlike that commonly observed with ruthenium complexes. Under the influence of MWs, Ru nanoparticles embedded in the nanomicelle environment were formed, acting as the effective hydration catalyst. Introducing sodium formate in the aqueous phase and using a stoichiometric amount of amines, the Ru nanoparticle nanomicelle catalyst gave the first example of one-pot single-step hydroamination of alkynes with the formation of the corresponding secondary amines. The reaction is characterized by low environmental impact as TGPS-750-M is required in low amount, and organic solvents employed only for product separation or catalyst recycling.
- Risi, Caterina,Cini, Elena,Petricci, Elena,Saponaro, Simone,Taddei, Maurizio
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supporting information
p. 1000 - 1003
(2020/01/22)
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- Boron-Catalyzed N-Alkylation of Arylamines and Arylamides with Benzylic Alcohols
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A sustainable boron-based catalytic approach for chemoselective N-alkylation of primary and secondary aromatic amines and amides with primary, secondary, and tertiary benzylic alcohols has been presented. The metal-free protocol operates at low catalyst loading, tolerates several functional groups, and generates H2O as the sole byproduct. Preliminary mechanistic studies were performed to demonstrate the crucial role of boron catalyst for the activation of the intermediate dibenzyl ether and to identify the rate-determining step.
- Guru, Murali Mohan,Thorve, Pradip Ramdas,Maji, Biplab
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p. 806 - 819
(2020/01/02)
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- Lithium bromide: an inexpensive and efficient catalyst for imine hydroboration with pinacolborane at room temperature
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An efficient protocol for the hydroboration of imines is reported. Lithium halide salts are effective catalysts to convert aldimines and ketimines to their corresponding amines. Here, we report excellent isolated yield of secondary amines (>95%) using 3 mol% lithium bromide in THF at room temperature. In addition, DFT calculations for a plausible reaction pathway are reported.
- An, Duk Keun,Hwang, Hyonseok,Kim, Hanbi,Kim, Hyun Tae,Lee, Ji Hye
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p. 34421 - 34427
(2020/10/12)
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- Chemoselective Reduction of Imines Catalyzed by Ruthenium(II) Half-Sandwich Complexes: A Mechanistic Study
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Ruthenium half-sandwich complexes ligated to chiral 2-oxazolidinethiones or 2-thiozolidinethiones in the reduction of N-benzylideneaniline using silyl hydrides as reductants has been examined. The chemoselective reduction of imines takes place under mild conditions to afford the corresponding amines in nearly quantitative yield. Mechanistic studies indicate that dissociation of the ancillary ligands generate the active catalyst in all the complexes studied, which is the same species generated by [Ru(p-cymene)(Cl)2]2 under the reaction conditions. This results in the formation of a single catalytic species irrespective of the starting half-sandwich complex. Detailed mechanistic studies involving trapping of intermediates, in situ studies using mass spectrometry and NMR spectroscopy were carried out using the active catalyst generated by [Ru(p-cymene)(Cl)2]2. The mechanism of the reaction is dependent on the number of the hydrogen atoms in the reducing silane. The reaction proceeds via Gade-Hoffman pathway or Zheng-Chan pathway when a dihydro or trihydrosilane is the reductant. However, the use of a monohydrosilane, leads to longer reaction times presumably due to a change in the reaction pathway.
- Reshi, Noor U. Din,Kathuria, Lakshay,Samuelson, Ashoka G.
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p. 2947 - 2955
(2019/06/27)
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- Synthesis and application of axially chiral biscarbolines with functional N-O and sulfone for 1,2-transfer hydrogenations of ketimines
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A series of axially chiral biscarboline-based sulfones were synthesized from L-tryptophane and applied for enantioselective 1,2-transfer hydrogenations of ketimines using trichlorosilane. The catalyst 4e, which had a tertiary butyl group, exhibited a good conversion and high enantioselectivities up to 96%ee in the series of reactions.
- Xing, Yongfei,Wu, Shijie,Dong, Mengxian,Wang, Jie,Liu, Li,Zhu, Huajie
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- Enhanced Catalytic Activity of Oxygen-Tethered IrIII NHC Complexes in Aqueous Transfer Hydrogenative Reductive Amination Reactions: Experimental Kinetic and Mechanistic Study
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The synthesis and characterization of seven new IrIII complexes containing o-phenoxide or o-naphthoxide chelated N-heterocyclic carbene ligands is reported herein. The crystal structures of six of the complexes have been determined. These complexes efficiently catalyze the transfer hydrogenative reductive amination (RA) of carbonyls and amines in water. Amongst the complexes tested, the introduction of o-naphthoxide on a nitrogen atom of imidazole based NHC ligand greatly increased the catalytic activity. The catalytic system has a broad substrate scope, which allows the synthesis of a variety of amines in excellent yields and with high turnover numbers up to 490 (for ketones) and 14800 (for aldehydes). The mechanism of aqueous RA reaction with an o-aryloxide chelated NHC-IrIII catalyst has been investigated by NMR spectroscopy and kinetic measurements. These studies suggest that the transfer hydrogenation (TH) is turnover-limited by the hydride formation step. As a result of the 1H NMR studies, the higher catalytic activity of o-naphthoxide chelated catalyst (3 g) over o-phenoxide chelated one (3 b) can be attributed partly due to the faster formation of an iridium hydride, the key intermediate in the RA reactions.
- ?zbozkurt, ?brahim Kayahan,Gülcemal, Derya,Günnaz, Salih,G?k?e, Ayta? Gürhan,?etinkaya, Bekir,Gülcemal, Süleyman
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p. 3593 - 3604
(2018/08/03)
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- Secondary amine compound synthesized from alkyne and synthesis method of secondary amine compound
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The invention relates to a secondary amine compound synthesized from alkyne and a synthesis method of the secondary amine compound. The specific structure of the compound is shown as the formula II inthe description. Meanwhile, the invention discloses the three-step one-pot synthesis method of the compound. According to the method, cheap and available acetenyl substituted benzene (I) is taken asa raw material. The method comprises steps as follows: step 1), fluorine-containing alcohol and water are taken as solvents and subjected to a hydration reaction under catalysis of trifluoromethanesulfonic acid, and an intermediate ketone is generated; step 2), aromatic amines are added directly to a reaction system, and imine is generated; step 3), tetrahydroxydiboron is added to the system, anda product II is obtained. No metal participates in the method, operation is simple and convenient, the raw materials are easily available, reaction conditions are mild, and yield is relatively high.
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Paragraph 0034; 0035; 0036
(2018/10/19)
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- Hofmann N-alkylation of aniline derivatives with alcohols using ferric perchlorate immobilized on SiO2 as a catalyst through Box–Behnken experimental design
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An efficient method for the N-alkylation of poorly nucleophilic amines using ferric perchlorate immobilized on SiO2 as a catalyst is described. Fe(ClO4)3 was prepared from mixing iron(III) hydroxide and perchloric acid and adsorbed on silica gel. The catalyst was characterized using various techniques. The supported ferric perchlorate (Fe(ClO4)3/SiO2) revealed high efficiency and selectivity for N-alkylation of aromatic amines with alcohols to provide alkylated amines. Various secondary amines were synthesized from primary amines and alcohols in good to excellent yields, with water as the only by-product. The optimization of the reaction conditions was investigated using the response surface method, and involving the Box–Behnken design matrix. The conditions for optimal reaction yield and time were: amount of catalyst?=?0.34?mmol, temperature?=?60°C and molar ratio of amine to alcohol?=?1.2. The catalyst was recovered and reused for five cycles without a considerable decrease in catalytic activity. The stability of the recycled catalyst was investigated. The proposed method has numerous advantages including procedure simplicity, short reaction times, low cost, good to excellent yields, reusability of the catalyst and mild and environmentally benign conditions.
- Ghanimati, Mahdi,Abdoli Senejani, Masumeh,Isfahani, Tahereh Momeni,Bodaghifard, Mohammad Ali
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- Cyclometalated Half-Sandwich Iridium Complex for Catalytic Hydrogenation of Imines and Quinolines
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Several C,N-chelate cyclometalated half-sandwich iridium-based catalysts for imines and quinoline derivatives reduction have been prepared through metal-mediated C-H bond activation based on benzothiazole ligands. These iridium complexes exhibited high catalytic activity for hydrogenation of various types of imines with high yields. The most active catalyst was obtained from methoxyl substituted complex 2, showing the catalytic TOF value of 975 h-1 for the reduction of imine 6a. Additionally, these half-sandwich complexes also showed high efficiency for the catalytic hydrogenation of N-heterocyclic quinoline derivatives. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. Complexes 1-5 were fully characterized by NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 4 were further confirmed by X-ray diffraction analysis.
- Yao, Zi-Jian,Lin, Nan,Qiao, Xin-Chao,Zhu, Jing-Wei,Deng, Wei
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p. 3883 - 3892
(2018/11/24)
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- B(C6F5)3-catalyzed transfer hydrogenations of imines with Hantzsch esters
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Highly efficient transfer hydrogenations of imines were realized with as low as 0.1 mol% of B(C6F5)3 by using Hantzsch esters as a hydrogen source, furnishing a variety of amines in 80-99% yields. For the asymmetric transf
- Wang, Qiaotian,Chen, Jingjing,Feng, Xiangqing,Du, Haifeng
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supporting information
p. 1448 - 1451
(2018/03/08)
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- Cobalt-Catalyzed Hydroarylations and Hydroaminations of Alkenes in Tunable Aryl Alkyl Ionic Liquids
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Tunable aryl alkyl ionic liquids (TAAILs) are a promising class of imidazolium- or triazolium-based ionic liquids. Contrary to "standard" all-alkyl ionic liquids, these carry an aryl ring together with a linear or branched alkyl chain. Their application i
- Schroeter, Felix,Lerch, Swantje,Kaliner, Maria,Strassner, Thomas
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supporting information
p. 6215 - 6219
(2018/10/05)
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- Method for catalyzing intermolecular hydroamination reaction of alkyne and amine
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The invention relates to a method for catalyzing intermolecular hydroamination reaction of alkyne and amine. The method comprises the following steps: reacting a terminal alkyne as shown in a formula (1) and a primary aromatic amine as shown in a formula
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Paragraph 0055-0058
(2018/03/01)
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- Nickel-Catalyzed N-Alkylation of Acylhydrazines and Arylamines Using Alcohols and Enantioselective Examples
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A borrowing-hydrogen reaction between amines and alcohols is an atom-economic way to prepare alkylamines, ideally with water as the sole byproduct. Herein, nickel catalysts are used for direct N-alkylation of hydrazides and arylamines using racemic alcohols. Moreover, a nickel catalyst of (S)-binapine was used for an asymmetric N-alkylation of benzohydrazide with racemic benzylic alcohols.
- Yang, Peng,Zhang, Caili,Ma, Yu,Zhang, Caiyun,Li, Aijie,Tang, Bo,Zhou, Jianrong Steve
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supporting information
p. 14702 - 14706
(2017/10/20)
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- Method for preparing secondary amine or N'-alkyl hydrazide through nickel catalysis N-alkylation reaction
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The invention discloses a method for preparing secondary amine or N'-alkyl hydrazide through nickel catalysis N-alkylation reaction. Amine or hydrazide is used as raw materials; alcohol is used as an alkylation agent; N-alkylation reaction is performed under the nickel catalysis condition; the secondary amine or N'-alkyl hydrazide is prepared. Compared with the prior art, the method provided by the invention has the advantages that the N-alkylation reaction is performed; active catalysts can be generated in situ by nickel salt and phosphine ligands; the preparation of catalysts in advance is avoided; the operation is simple and convenient; the experiment steps and the experiment cost are reduced. Cheap nickel is used as the catalysts; the consumption of the catalysts is low; the use of expensive and high-toxicity precious metal is avoided; the experiment cost is further reduced; the hydrogen borrowing strategy is utilized; the N'-alkylation of the hydrazide is realized for the first time; byproducts only contain water. Compared with other preparation methods, the method has the advantage that the reaction environment-friendly performance is realized.
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Paragraph 0053; 0054; 0055; 0056; 0057
(2017/12/27)
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- Exploiting Deep Eutectic Solvents and Organolithium Reagent Partnerships: Chemoselective Ultrafast Addition to Imines and Quinolines Under Aerobic Ambient Temperature Conditions
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Shattering the long-held dogma that organolithium chemistry needs to be performed under inert atmospheres in toxic organic solvents, chemoselective addition of organolithium reagents to non-activated imines and quinolines has been accomplished in green, b
- Vidal, Cristian,García-álvarez, Joaquín,Hernán-Gómez, Alberto,Kennedy, Alan R.,Hevia, Eva
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supporting information
p. 16145 - 16148
(2016/12/26)
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- Commercial Supported Gold Nanoparticles Catalyzed Alkyne Hydroamination and Indole Synthesis
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Commercial gold nanoparticles supported on titanium dioxide (TiO2) were found to be a highly efficient catalyst for alkyne hydroamination. Terminal alkynes could easily undergo intermolecular hydroamination with low catalyst loadings (0.2 mol% Au) under solvent-free conditions. Indoles were efficiently synthesized using microwave heating through intramolecular hydroamination. (Figure presented.).
- Liang, Shengzong,Hammond, Luisa,Xu, Bo,Hammond, Gerald B.
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p. 3313 - 3318
(2016/10/21)
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- A Highly Efficient Base-Metal Catalyst: Chemoselective Reduction of Imines to Amines Using An Abnormal-NHC-Fe(0) Complex
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A base-metal, Fe(0)-catalyzed hydrosilylation of imines to obtain amines is reported here which outperforms its noble-metal congeners with the highest TON of 17000. The catalyst, (aNHC)Fe(CO)4, works under very mild conditions, with extremely low catalyst loading (down to 0.005 mol %), and exhibits excellent chemoselectivity. The facile nature of the imine reduction under mild conditions has been further demonstrated by reducing imines towards expensive commercial amines and biologically important N-alkylated sugars, which are difficult to achieve otherwise. A mechanistic pathway and the source of chemoselectivity for imine hydrosilylation have been proposed on the basis of the well-defined catalyst and isolable intermediates along the catalytic cycle.
- Bhunia, Mrinal,Hota, Pradip Kumar,Vijaykumar, Gonela,Adhikari, Debashis,Mandal, Swadhin K.
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supporting information
p. 2930 - 2937
(2016/10/06)
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- A New Phenoxide Chelated IrIII N-Heterocyclic Carbene Complex and Its Application in Reductive Amination Reactions
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A new phenoxide chelated [Ir(NHC)CpCl] (NHC = N-heterocyclic carbene; Cp = pentamethylcyclopentadienyl) complex (3) has been prepared by reaction of [IrCpCl2]2 with an in situ prepared NHC-Ag complex in dichloromethane at ambient temperature. The IrIII complex was stable toward air and moisture and was fully characterized by 1H, 13C NMR, HRMS, and single-crystal X-ray diffraction. The new complex was found to be an active catalyst for transfer hydrogenative reductive amination under aqueous conditions with formate as hydrogen source as well as hydrogenative reductive amination reactions using H2. Various carbonyl compounds such as aliphatic and aromatic ketones and aldehydes were successfully reacted with amines to give new amines. In comparison with transfer hydrogenative reductive amination, the reductive amination with H2 is faster and permits higher molar ratios of the substrate to the catalyst (S/C).
- Gülcemal, Derya,Gülcemal, Süleyman,Robertson, Craig M.,Xiao, Jianliang
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p. 4394 - 4400
(2015/09/22)
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- Zirconium complexes stabilized by amine-bridged bis(phenolato) ligands as precatalysts for intermolecular hydroamination reactions
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A series of zirconium complexes bearing amine-bridged bis(phenolato) ligands of different steric and electronic properties have been synthesized, and their activities in catalyzing intermolecular hydroamination reactions have been studied and compared. In
- Sun, Qiu,Wang, Yaorong,Yuan, Dan,Yao, Yingming,Shen, Qi
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p. 20352 - 20360
(2015/12/04)
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- Highly chemoselective reduction of imines using a AuNPore/PhMe2SiH/water system and its application to reductive amination
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Abstract An unusually strong affinity of unsupported nanoporous gold (AuNPore) towards aldimines and ketimines has been demonstrated. By using PhMe2SiH and water as a hydrogen source and AuNPore as a catalyst, ketimines and aldimines can be reduced to the corresponding amines in high chemical yields under mild conditions. This system was also applied to the reductive amination of aldehydes and ketones.
- Takale, Balaram S.,Tao, Shanmou,Yu, Xiaoqiang,Feng, Xiujuan,Jin, Tienan,Bao, Ming,Yamamoto, Yoshinori
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p. 7154 - 7158
(2015/08/24)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 0314; 0325
(2015/03/28)
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- Indium-catalyzed hydroamination/hydrosilylation of terminal alkynes and aromatic amines through a one-pot, two-step protocol
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We demonstrated that indium tribromide effectively functioned as a single catalyst for two successive steps in a one-pot procedure. First, the hydroamination of alkynes with anilines took place to give the Markovnikov product. Then, hydrosilylation of the imine intermediates by treatment with a hydrosilane substrate afforded the corresponding secondary amines.
- Sakai, Norio,Takahashi, Nobuaki,Ogiwara, Yohei
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supporting information
p. 5078 - 5082
(2014/08/18)
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- Synthesis of group 4 metal complexes stabilized by an amine-bridged bis(phenolato) ligand and their catalytic behavior in intermolecular hydroamination reactions
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Zirconium and titanium complexes 1 and 2, bearing an amine-bridged bis(phenolato) ligand, have been synthesized and characterized. Although 1 and 2 were inactive in catalyzing intermolecular hydroamination reactions, cationic complexes generated in situ f
- Sun, Qiu,Wang, Yaorong,Yuan, Dan,Yao, Yingming,Shen, Qi
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p. 994 - 1001
(2014/03/21)
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- Simple and efficient AuI-based catalyst for hydroamination of alkynes
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Hydroamination of terminal alkynes with anilines in the presence of (C6F5)3PAuNTf2 catalyst affords 2-aryliminoalkanes whose reduction in situ with sodium borohydride gives the corresponding secondary amines in
- Anokhin, Maksim V.,Murashkina, Arina V.,Averin, Alexei D.,Beletskaya, Irina P.
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p. 332 - 333
(2015/02/19)
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- Rhenium-catalyzed amination of alcohols by hydrogen transfer process
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The rhenium heptahydride complex [ReH7(PCy3) 2] was found to be an effective homogeneous catalyst for amination of various alcohols through hydrogen transfer mechanism. Under carbon monoxide atmosphere, a variety of primary and secondary alcohols could directly undergo the CN coupling process.
- Abdukader, Ablimit,Jin, Hongming,Cheng, Yixiang,Zhu, Chengjian
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supporting information
p. 4172 - 4174
(2014/07/22)
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- Fast reductive amination by transfer hydrogenation "on water"
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Reductive amination of various ketones and aldehydes by transfer hydrogenation under aqueous conditions has been developed, by using cyclometallated iridium complexes as catalysts and formate as hydrogen source. The pH value of the solution is shown to be critical for a high catalytic chemoselectivity and activity, with the best pH value being 4.8. In comparison with that in organic solvents, the reductive amination in an aqueous phase is faster, and the molar ratio of the substrate to the catalyst (S/C) can be set as high as 1×105, the highest S/C value ever reported in reductive amination reactions. The catalyst is easy to access and the reaction is operationally simple, allowing a wide range of ketones and aldehydes to react with various amines in high yields. The protocol provides a practical and environmental friendly new method for the synthesis of amine compounds. Greener amine synthesis: A versatile reductive amination protocol has been developed. By using an iridium catalyst in water, a broad range of ketones and aldehydes react with amines to afford various new amines in good yields (see scheme), with molar ratios of the substrate to the catalyst (S/C) as high as 1×10 5. The pH of the reaction solution plays a key role, regulating both the catalytic activity and the selectivity. Copyright
- Lei, Qian,Wei, Yawen,Talwar, Dinesh,Wang, Chao,Xue, Dong,Xiao, Jianliang
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supporting information
p. 4021 - 4029
(2013/04/10)
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- Solvent- and catalyst-free direct reductive amination of aldehydes and ketones with Hantzsch ester: Synthesis of secondary and tertiary amines
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A facile and rapid method for the parallel synthesis of a series of secondary and tertiary amines by the direct reductive amination of aldehydes and ketones with Hantzsch ester under solvent- and catalyst-free has been developed. The scope and limitation of this method are described.
- Nguyen, Quynh Pham Bao,Kim, Taek Hyeon
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p. 4938 - 4943
(2013/07/25)
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- One-pot transformation of alkynes into alcohols and amines with formic acid
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Alkynes are converted into alcohols and amines through a formic acid-participated alkyne-to-ketone transformation and transfer hydrogenation process. The reaction proceeds well under aqueous conditions, furnishing chiral alcohols directly from alkynes for the first time.
- Li, Jia,Wang, Chao,Xue, Dong,Wei, Yawen,Xiao, Jianliang
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supporting information
p. 2685 - 2689
(2013/10/08)
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- Simple, efficient and reusable Pd-NHC catalysts for hydroamination
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A series of chelating NHC-palladium complexes with different alkane-bridges of the type Pd[NHC-(CH2)n-NHC]X2 (X = Br or Cl, n = 2-4) were synthesized, where NHC is a triazolyl-N-heterocyclic carbene donor ligand. The bromi
- Chen, Qian,Lv, Lanlan,Yu, Meng,Shi, Yanhui,Li, Yuling,Pang, Guangsheng,Cao, Changsheng
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p. 18359 - 18366
(2013/10/21)
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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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- (Cyclopentadienyl)iron(II) complexes of N-heterocyclic carbenes bearing a malonate or imidate backbone: Synthesis, structure, and catalytic potential in hydrosilylation
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The backbone-functionalized anionic carbenes maloNHC (1R; malonate backbone) and imidNHC (2; imidate backbone) were generated in situ from their respective zwitterionic precursors and treated with FeCp(CO)2I to afford the zwitterionic complexes {FeCp(CO)2(1R)} (3R; 59-84% yield), and {FeCp(CO)2(2)} (4; 77% yield), respectively. Methylation of the malonate complex 3Me takes place at one of the backbone oxygen atoms to give the cationic adduct [FeCp(CO) 2(1MeMe)](OTf) ([5Me](OTf); 96% yield), whereas methylation of 4 takes place at the imidate nitrogen atom to produce the cationic adduct [FeCp(CO)2(2Me)](OTf) ([6 Me](OTf); 84% yield). All of the complexes were characterized by NMR and IR in solution, while X-ray structure analyses were carried out for 3 Me, 4, and [6Me](OTf). In addition, a detailed experimental and theoretical investigation of the electron density within the archetypal zwitterionic complex 3Me was carried out. The observation of short intramolecular contacts between Cipso or Cortho of the mesityl groups of the carbene and the proximal carbonyl groups is rationalized in terms of a noncovalent "through space" π-π* interaction involving a two-electron delocalization of the occupied π(Cipso=Cortho) molecular orbital (MO) of the aryl ring into one vacant π*(C≡O) MO of the carbonyl ligand. A theoretical analysis carried out on dissymmetrical model complexes reveals that the magnitude of such an interaction is correlated with the donor properties of aryl group substituents. A catalyst screening of the above complexes in the hydrosilylation of benzaldehyde under visible light irradiation revealed a dramatic effect of the electronic donor properties of these carbenes on the performances of their complexes, with the more nucleophilic carbene 1 tBu- in the zwitterionic species 3tBu appearing as the most efficient. This complex shows good efficiency and excellent chemoselectivity in the hydrosilylation of various aldehydes bearing reactive functional groups. It is also moderately active in the hydrosilylation of a few ketone substrates and exhibits very good performance in the hydrosilylation of representative aldimines and ketimines.
- Cesar, Vincent,Misal Castro, Luis C.,Dombray, Thomas,Sortais, Jean-Baptiste,Darcel, Christophe,Labat, Stephane,Miqueu, Karinne,Sotiropoulos, Jean-Marc,Brousses, Remy,Lugan, Noel,Lavigne, Guy
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supporting information
p. 4643 - 4655
(2013/09/23)
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- Cyclopentadienyl N-heterocyclic carbene-nickel complexes as efficient pre-catalysts for the hydrosilylation of imines
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The in situ generated nickel hydride complex, [Ni(Mes2NHC)HCp], and its cationic analogue, [Ni(Mes2NHC)(NCMe)Cp](PF6), are efficient and chemoselective pre-catalysts for the hydrosilylation of both aldimines and ketimines under mild conditions. The Royal Society of Chemistry.
- Bheeter, Linus P.,Henrion, Mickael,Chetcuti, Michael J.,Darcel, Christophe,Ritleng, Vincent,Sortais, Jean-Baptiste
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p. 3111 - 3116
(2013/12/04)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 00163; 00174
(2013/11/05)
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- S-benzyl isothiouronium chloride as a recoverable organocatalyst for the direct reductive amination of ketones with Hantzsch ester
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The direct reductive amination of ketones using the Hantzsch ester in the presence of S-benzyl isothiouronium chloride as a recoverable organocatalyst is reported. A wide range of ketones as well as amines were found to give the expected products in moder
- Nguyen, Quynh Pham Bao,Kim, Taek Hyeon
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experimental part
p. 1977 - 1982
(2012/08/07)
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- Catalytic C-H Amination with aromatic amines
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Aniline joins the club: A β-diketiminato copper(I) catalyst enables C-H amination of anilines employing low catalyst loadings to preclude oxidation to the diazene ArNi-NAr (see scheme). Electron-poor anilines are particularly resistant towards diazene formation and participate in the amination of strong and unactivated C-H bonds. N-alkyl anilines also take part in C-H amination. Copyright
- Gephart III, Raymond T.,Huang, Daria L.,Aguila, Mae Joanne B.,Schmidt, Graham,Shahu, Andi,Warren, Timothy H.
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supporting information; experimental part
p. 6488 - 6492
(2012/07/30)
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- NHC-carbene cyclopentadienyl iron based catalyst for a general and efficient hydrosilylation of imines
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A general and efficient hydrosilylation of imines catalysed by a well defined NHC-carbene cyclopentadienyl iron complex has been developed. Both aldimines and ketimines are converted to the corresponding amines under mild conditions, and under visible light activation.
- Castro, Luis C. Misal,Sortais, Jean-Baptiste,Darcel, Christophe
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supporting information; experimental part
p. 151 - 153
(2012/01/06)
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- Amine synthesis through mild catalytic hydrosilylation of imines using polymethylhydroxysiloxane and [RuCl2(arene)]2 catalysts
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Tolerate silicone! The stable [RuCl2(p-cymene]2 complex is an efficient catalyst for the direct chemoselective hydrosilylation of functionalized aldimines and ketimines into amines, using polymethylhydroxysiloxane as an inexpensive, stable, and safe hydrosilane source. The catalysis operates in ethanol, under air at room temperature, and tolerates the ketone ester and alkene functionality. Copyright
- Li, Bin,Sortais, Jean-Baptiste,Darcel, Christophe,Dixneuf, Pierre H.
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experimental part
p. 396 - 399
(2012/06/01)
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- Zirconium-catalyzed intermolecular hydroamination of alkynes with primary amines
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A simple catalyst system generated in situ by combination of 5 mol-% [Zr(NMe2)4] and 10 mol-% of a sulfonamide catalyzes the intermolecular hydroamination of alkynes with primary amines. At elevated temperatures, hydroamination is achieved with both internal and terminal alkynes as well as with sterically demanding and less demanding primary amines. In contrast, secondary amines do not react under identical conditions. Of the sulfonamide additives investigated, sterically demanding tosylamides such as N-(tert-butyl)-p-toluenesulfonamide give the best results. The regioselectivity of the addition of amine to unsymmetrically substituted internal as well as terminal alkynes is significantly influenced by the nature of the sulfonamide additive. In particular, the successful use of sterically less demanding primary amines such as n-hexyl-or benzylamine clearly indicates that the assumption that Zr catalysts generally form catalytically inactive bridging μ2-imido dimers or other unreactive intermediates in the presence of these amines is not correct. Intermolecular hydroamination reactions of alkynes with primary amines that are sterically less demanding than 2,6-dimethylaniline can be achieved with in situ generated zirconium catalysts. This finding is highly important for a better and more general understanding of the mechanism of group 4 metal-catalyzed hydroamination reactions. Copyright
- Born, Karolin,Doye, Sven
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experimental part
p. 764 - 771
(2012/03/22)
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- Palladium-catalyzed asymmetric hydrogenation of simple ketimines using a Bronsted acid as activator
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Using a catalytic amount of a Bronsted acid as activator of simple imines, the highly enantioselective homogeneous palladium-catalyzed asymmetric hydrogenation of simple ketimines was successfully developed with up to 95% ee.
- Zhou, Xiao-Yu,Bao, Ming,Zhou, Yong-Gui
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supporting information; experimental part
p. 84 - 88
(2011/03/23)
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