- Hydroborative reduction of amides to amines mediated by La(CH2C6H4NMe2-: O)3
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The deoxygenative reduction of amides to amines is a great challenge for resonance-stabilized carboxamide moieties, although this synthetic strategy is an attractive approach to access the corresponding amines. La(CH2C6H4NMe2-o)3, a simple and easily accessible lanthanide complex, was found to be highly efficient not only for secondary and tertiary amide reduction, but also for the most challenging primary reduction with pinacolborane. This protocol exhibited good tolerance for many functional groups and heteroatoms, and could be applied to gram-scale synthesis. The active species in this catalytic cycle was likely a lanthanide hydride.
- Gong, Mingliang,Guo, Chenjun,Luo, Yunjie,Xie, Hongzhen,Zhang, Fangcao
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p. 779 - 791
(2022/01/22)
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- Cp*Ir complex bearing a flexible bridging and functional 2,2′-methylenebibenzimidazole ligand as an auto-tandem catalyst for the synthesis of N-methyl tertiary amines from imines via transfer hydrogenation/N-methylation with methanol
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A Cp*Ir complex bearing a flexible bridging and functional 2,2′-methylenebibenzimidazole ligand was designed, synthesized, and found to be a general and efficient auto-tandem catalyst for the synthesis of N-methyl tertiary amines from imines via transfer hydrogenation/N-methylation with methanol as both hydrogen source and methylating reagent. In the presence of [Cp*Ir(2,2′-CH2BiBzImH2)Cl][Cl], a range of desirable products were obtained in high yields with nearly complete selectivities. The reaction is highly attractive due to the highly atom economy, and minimal consumption of chemicals and energy. Notably, this research exhibits new potential of metal–ligand bifunctional catalysts for the activation of methanol as C1 source for organic synthesis.
- Ai, Yao,Chen, Xiaozhong,Li, Feng,Liu, Peng,Yang, Chenchen,Yang, Jiazhi
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p. 325 - 334
(2021/10/07)
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- Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
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Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
- Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
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supporting information
p. 13122 - 13135
(2021/08/31)
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- Homoleptic Bis(trimethylsilyl)amides of Yttrium Complexes Catalyzed Hydroboration Reduction of Amides to Amines
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Homoleptic lanthanide complex Y[N(TMS)2]3 is an efficient homogeneous catalyst for the hydroboration reduction of secondary amides and tertiary amides to corresponding amines. A series of amides containing different functional groups such as cyano, nitro, and vinyl groups were found to be well-tolerated. This transformation has also been nicely applied to the synthesis of indoles and piribedil. Detailed isotopic labeling experiments, control experiments, and kinetic studies provided cumulative evidence to elucidate the reaction mechanism.
- Ye, Pengqing,Shao, Yinlin,Ye, Xuanzeng,Zhang, Fangjun,Li, Renhao,Sun, Jiani,Xu, Beihang,Chen, Jiuxi
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p. 1306 - 1310
(2020/02/22)
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- Iridium-Catalyzed Alkylation of Amine and Nitrobenzene with Alcohol to Tertiary Amine under Base- and Solvent-Free Conditions
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Herein, an efficient and green method for the selective synthesis of tertiary amines has been developed that involves iridium-catalyzed alkylation of various primary amines with aromatic or aliphatic alcohols. Notably, the catalytic protocol enables this transformation in the absence of additional base and solvent. Furthermore, the alkylation of nitrobenzene with primary alcohol to tertiary amine has also been achieved by the same catalytic system. Deuterium-labeling experiments and a series of control experiments were conducted, and the results suggested that an intermolecular borrowing hydrogen pathway might exist in the alkylation process.
- Li, Chao,Wan, Ke-Feng,Guo, Fu-Ya,Wu, Qian-Hui,Yuan, Mao-Lin,Li, Rui-Xiang,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua
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p. 2158 - 2168
(2019/05/16)
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- Simple Metal-Free Direct Reductive Amination Using Hydrosilatrane to Form Secondary and Tertiary Amines
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This work describes the use of cheap, safe, and easy-to-handle hydrosilatrane as the reductant in direct reductive amination reactions. This efficient method enables a facile, metal-free access to secondary and tertiary amines from a wide range of aldehydes and ketones, with the synthesis of tertiary amines requiring no additives at all. This reaction demonstrates excellent functional group tolerance, chemoselectivity, and scalability. (Figure presented.).
- Varjosaari, Sami E.,Skrypai, Vladislav,Suating, Paolo,Hurley, Joseph J. M.,Lio, Ashley M. De,Gilbert, Thomas M.,Adler, Marc J.
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supporting information
p. 1872 - 1878
(2017/06/09)
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- Synthesis of the cyclopentadienone rhodium complexes and investigation of their catalytic activity in the reductive amination of aldehydes in the presence of carbon monoxide
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Reaction of bis(p-tolyl-propargyl)-tosylamide with [(cod)RhCl]2in the presence of CO gives the cyclopentadienone complex [(Cpd’)Rh(CO)Cl]n(Cpd’ = TsN(CH2)2C4(Tol)2CO). Its dissolution in DM
- Pototskiy, Roman A.,Afanasyev, Oleg I.,Nelyubina, Yulia V.,Chusov, Denis,Kudinov, Alexander R.,Perekalin, Dmitry S.
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supporting information
p. 6 - 11
(2017/03/02)
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- Scalable synthesis of secondary and tertiary amines by heterogeneous Pt-Sn/γ-Al2O3catalyzed N-alkylation of amines with alcohols
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Synthesis of secondary and tertiary amines has been efficiently realized from the N-alkylation of amines with alcohols by means of heterogeneous bimetallic Pt-Sn/γ-Al2O3catalyst (0.5?wt % Pt, molar ratio Pt:Sn?=?1:3) through a borrowing hydrogen strategy. The Pt-Sn/γ-Al2O3catalyst has exhibited very high catalytic activity towards a wide range of amines and alcohols, and can be conveniently recycled without Pt metal leaching. The present protocol was applied for the synthesis of N-phenylbenzylamine in 96% isolated yield from aniline and benzyl alcohol on a 2.1?kg scale of the substrates, demonstrating its potential applicability for higher-order amine synthesis.
- Wu, Kaikai,He, Wei,Sun, Chenglin,Yu, Zhengkun
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supporting information
p. 8516 - 8521
(2016/11/28)
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- Cyclobutadiene Metal Complexes: A New Class of Highly Selective Catalysts. An Application to Direct Reductive Amination
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A catalyst of a new type, cyclobutadiene complex [(C4Et4)Rh(p-xylene)]PF6, was found to promote selective reductive amination in the presence of carbon monoxide under mild conditions (1-3 bar, 90 °C). The reaction demonstr
- Afanasyev, Oleg I.,Tsygankov, Alexey A.,Usanov, Dmitry L.,Perekalin, Dmitry S.,Shvydkiy, Nikita V.,Maleev, Victor I.,Kudinov, Alexander R.,Chusov, Denis
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p. 2043 - 2046
(2016/03/15)
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- Reductive Transformations of Carbonyl Compounds Catalyzed by Rhodium Supported on a Carbon Matrix by using Carbon Monoxide as a Deoxygenative Agent
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An efficient method for the rhodium on carbon matrix catalyzed preparation of secondary and tertiary amines, cyanoesters, and nitriles through the reductive amination/alkylation of carbonyl compounds was developed, including a convenient procedure for the tandem formal reductive addition of acetonitrile to aldehydes. The catalyst could be reused, and at least three consecutive reaction cycles were performed with comparable efficiency. The method was shown to be compatible with functional groups prone to reduction by hydrogen and complex hydrides. Beyond the matrix: An efficient method for the rhodium on carbon matrix catalyzed preparation of secondary and tertiary amines, cyanoesters, and nitriles through the reductive amination/alkylation of carbonyl compounds is developed, including a convenient procedure for the tandem formal reductive addition of acetonitrile to aldehydes. TON=turnover number.
- Yagafarov, Niyaz Z.,Usanov, Dmitry L.,Moskovets, Alexey P.,Kagramanov, Nikolai D.,Maleev, Victor I.,Chusov, Denis
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p. 2590 - 2593
(2015/09/15)
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
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supporting information
p. 9349 - 9352
(2014/08/05)
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- Mild hydrosilylation of amides by platinum N-heterocyclic carbene catalysts
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The platinum-catalyzed hydrosilylation of amides to afford amines selectively is reported. By using defined platinum/N-heterocyclic carbene complexes, the reduction of secondary and tertiary amines takes place under mild conditions. The selective catalytic hydrosilylation of amides is reported. By using defined platinum/N-heterocyclic carbene (NHC) complexes, the reduction of secondary and tertiary amines proceeds in good yields under mild conditions. Copyright
- Pisiewicz, Sabine,Junge, Kathrin,Beller, Matthias
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supporting information
p. 2345 - 2349
(2014/06/09)
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- Mild hydrosilylation of amides by platinum N-heterocyclic carbene catalysts
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The platinum-catalyzed hydrosilylation of amides to afford amines selectively is reported. By using defined platinum/N-heterocyclic carbene complexes, the reduction of secondary and tertiary amines takes place under mild conditions. The selective catalytic hydrosilylation of amides is reported. By using defined platinum/N-heterocyclic carbene (NHC) complexes, the reduction of secondary and tertiary amines proceeds in good yields under mild conditions.
- Pisiewicz, Sabine,Junge, Kathrin,Beller, Matthias
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supporting information
p. 2345 - 2349
(2015/04/27)
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- Coordination chemistry and catalytic activity of ruthenium(II) complexes containing a phospha-macrocyclic ligand
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Substitution of [RuCl2(CO)3(THF)], [RuCl 2(dmso)4] and [RuCl2(PPh3) 3] with a macrocyclic ligand, 2,3,4,5,6,7,8,9-octahydro-1,9-diphenyl- 1H-5,1,9-benzazadiphosphacyclo undecine (11-P2NH), provided [Ru(11-P2NH)Cl2(CO)] (3), [Ru(11-P2NH)Cl 2(dmso)] (4) and [Ru(11-P2NH)Cl2(CH 3CN)] (5), respectively. These complexes were characterized by elemental analyses as well as NMR spectroscopy. The structure of 3 was further confirmed by X-ray diffraction analysis. The octahedral geometry around the ruthenium center is in agreement with the Werner's "coordination" bonding concepts. The chelate rings of the macrocycle toward Ru(II) center adopting into chair conformations were revealed. Furthermore, these ruthenium complexes were found to be active for N-alkylation of dibenzylamine with alcohols.
- Lee, Chun-Chin,Huang, Hsiao-Ching,Liu, Shiuh-Tzung,Liu, Yi-Hung,Peng, Shie-Ming,Chen, Jwu-Ting
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p. 1024 - 1029
(2013/06/05)
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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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p. 11039 - 11050
(2013/09/02)
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- Preparation of secondary and tertiary amines from nitroarenes and alcohols
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Various secondary amines were obtained selectively from the reaction of nitroarenes with primary alcohols in the presence of ruthenium(ii) complexes having phosphine-amine ligands as the catalyst. Secondary amines could be further alkylated with a primary alcohol using the same catalyst, but different conditions.
- Lee, Chun-Chin,Liu, Shiuh-Tzung
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supporting information; experimental part
p. 6981 - 6983
(2011/08/06)
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- The "borrowing hydrogen strategy" by supported ruthenium hydroxide catalysts: Synthetic scope of symmetrically and unsymmetrically substituted amines
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The N-alkylation of ammonia (or its surrogates, such as urea, NH 4HCO3, and (NH4)2CO3) and amines with alcohols, including primary and secondary alcohols, was efficiently promoted under anaerobic conditions by the easily prepared and inexpensive supported ruthenium hydroxide catalyst Ru(OH)x/TiO2. Various types of symmetrically and unsymmetrically substituted "tertiary" amines could be synthesized by the N-alkylation of ammonia (or its surrogates) and amines with "primary" alcohols. On the other hand, the N-alkylation of ammonia surrogates (i.e., urea and NH 2HCO3) with "secondary" alcohols selectively produced the corresponding symmetrically substituted "secondary" amines, even in the presence of excess amounts of alcohols, which is likely due to the steric hindrance of the secondary alcohols and/or secondary amines produced. Under aerobic conditions, nitriles could be synthesized directly from alcohols and ammonia surrogates . The observed catalysis for the present N-alkylation recations was intrinsically heterogeneous, and the retrieved catalyst could be reused without any significant loss of catalytic performance. The present catalytic transformation would proceed through consecutive N-alkylation reactions, in which alcohols act as alkylating reagents. On the basis of deuterium-labeling experiments, the formation of the ruthenium dihydride species is suggested during the N-alkylation reactions.
- Yamaguchi, Kazuya,He, Jinling,Oishi, Takamichi,Mizuno, Noritaka
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scheme or table
p. 7199 - 7207
(2010/09/05)
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- Amide activation by Tf2O: Reduction of amides to amines by NaBH4 under mild conditions
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An expeditious and practical method for the reduction of amides to amines is reported. The method is consisted of activation of amides with Tf 2O followed by reduction with sodium borohydride in THF at room temperature. Various amides/lactams gave the corresponding amines in good to excellent yields, even with hindered amides and secondary amides. This method also presents other advantages such as TBDPS-group tolerance, short reaction time, simple workup and purification procedure. Georg Thieme Verlag Stuttgart.
- Xiang, Shao-Hua,Xu, Jian,Yuan, Hong-Qiu,Huang, Pei-Qiang
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supporting information; experimental part
p. 1829 - 1832
(2010/10/02)
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- A convenient and general iron-catalyzed reduction of amides to amines
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While the iron is hot: The first general and efficient iron-catalyzed reduction of secondary and tertiary amides into amines using polymethylhydrosiloxane (PMHS) has been developed (see scheme).
- Zhou, Shaolin,Junge, Kathrin,Addis, Daniele,Das, Shoubhik,Beller, Matthias
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supporting information; experimental part
p. 9507 - 9510
(2010/03/24)
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