588-47-6Relevant academic research and scientific papers
Ruthenium(ii) complexes with N-heterocyclic carbene-phosphine ligands for theN-alkylation of amines with alcohols
Huang, Ming,Li, Yinwu,Lan, Xiao-Bing,Liu, Jiahao,Zhao, Cunyuan,Liu, Yan,Ke, Zhuofeng
supporting information, p. 3451 - 3461 (2021/05/03)
Metal hydride complexes are key intermediates forN-alkylation of amines with alcohols by the borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols and the hydrogenation of imines. Herein we report ruthenium(ii) complexes with hetero-bidentate N-heterocyclic carbene (NHC)-phosphine ligands, which realize smart pathway selection in theN-alkylated reactionviareactivity tuning of [Ru-H] species by hetero-bidentate ligands. In particular, complex6cbwith a phenyl wingtip group and BArF?counter anion, is shown to be one of the most efficient pre-catalysts for this transformation (temperature is as low as 70 °C, neat conditions and catalyst loading is as low as 0.25 mol%). A large variety of (hetero)aromatic amines and primary alcohols were efficiently converted into mono-N-alkylated amines in good to excellent isolated yields. Notably, aliphatic amines, challenging methanol and diamines could also be transformed into the desired products. Detailed control experiments and density functional theory (DFT) calculations provide insights to understand the mechanism and the smart pathway selectionvia[Ru-H] species in this process.
Cobalt encapsulated in N?doped graphene sheet for one-pot reductive amination to synthesize secondary amines
Liu, Lin,Li, Wenxiu,Qi, Ran,Zhu, Qingqing,Li, Jing,Fang, Yuzhen,Kong, Xiangjin
, (2021/03/14)
To develop an efficient base-metal reductive amination catalyst for synthesis of secondary amines is still a major challenge. In this study, an efficient N-doped graphene sheet-coated cobalt catalyst (Co@CN-800) was developed through a simple pyrolysis process, which could gave 99.5 % yield of N-benzylaniline by one-pot reductive amination of nitrobenzene with benzaldehyde during at least 5 cycles. Catalyst characterization and control experiments confirmed that the robust catalytic performance of the catalyst is probably due to the synergy effect of in situ generated Co-Nx encapsulated in N?doped graphene layer and appropriate meso-pore structure. Additionally, The substrate adaptability of the catalyst was proved since a variety of corresponding secondary amines were smoothly obtained under relatively mild conditions, which makes the secondary amine synthesis strategy based on Co@CN-800 shows excellent application prospect.
Reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3as a reductant
Zou, Qizhuang,Liu, Fei,Zhao, Tianxiang,Hu, Xingbang
supporting information, p. 8588 - 8591 (2021/09/04)
Herein, we report the first example of efficient reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3 as a catalyst and a reductant under mild conditions, affording various tertiary and secondary amines in excellent yields. A mechanistic study indicates that BH3N(C2H5)3 plays a dual function role of promoting imine and iminium formation and serving as a reductant in reductive amination. This journal is
Direct N-Alkylation/Fluoroalkylation of Amines Using Carboxylic Acids via Transition-Metal-Free Catalysis
Lu, Chunlei,Qiu, Zetian,Xuan, Maojie,Huang, Yan,Lou, Yongjia,Zhu, Yiling,Shen, Hao,Lin, Bo-Lin
supporting information, p. 4151 - 4158 (2020/08/21)
A scalable protocol of direct N-mono/di-alkyl/fluoroalkylation of primary/secondary amines has been constructed with various carboxylic acids as coupling agents under the catalysis of a simple air-tolerant inorganic salt, K3PO4. Advantageous features include 100 examples, 10 drugs and drug-like amines, fluorinated complex tertiary amines, gram-scale synthesis and isotope-labelling amine, thus demonstrating the potential applicability in industry of this methodology. The involvement of relatively less reactive silicon-hydride compared with the traditional reactive metal-hydride or boron-hydride species required to reduce the amide intermediates presumably contributes to the remarkable functional group compatibility. (Figure presented.).
Linear Hydroaminoalkylation Products from Alkyl-Substituted Alkenes
Warsitz, Michael,Doye, Sven
supporting information, p. 15121 - 15125 (2020/10/23)
The regioselective conversion of alkyl-substituted alkenes into linear hydroaminoalkylation products represents a strongly desirable synthetic transformation. In particular, such conversions of N-methylamine derivatives are of great scientific interest, because they would give direct access to important amines with unbranched alkyl chains. Herein, we present a new one-pot procedure that includes an initial alkene hydroaminoalkylation with an α-silylated amine substrate and a subsequent protodesilylation reaction that delivers linear hydroaminoalkylation products with high selectivity from simple alkyl-substituted alkenes. For that purpose, new titanium catalysts have been developed, which are able to activate the α-C?H bond of more challenging α-silylated amine substrates. In addition, a direct relationship between the ligand structure of the new catalysts and the obtained regioselectivity is described.
Colloidal and Nanosized Catalysts in Organic Synthesis: XXIII. Reductive Amination of Carbonyl Compounds Catalyzed by Nickel Nanoparticles in a Plug-Flow Reactor
Mokhov, V. M.,Nebykov, D. N.,Paputina, A. N.,Popov, Yu. V.,Shishkin, E. V.
, p. 2333 - 2340 (2020/02/25)
Reductive amination of aldehydes and ketones with primary and secondary amines under catalysis with nickel nanoparticles supported on zeolite X, MgO, or activated carbon in the gas phase or in the gas-liquid system in a plug-flow reactor proceeds at atmospheric pressure of hydrogen with the formation of secondary or tertiary amines in high yield.
B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
supporting information, p. 2301 - 2308 (2019/01/30)
The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
supporting information, p. 3800 - 3806 (2019/07/12)
A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
Borrowing Hydrogen-Mediated N-Alkylation Reactions by a Well-Defined Homogeneous Nickel Catalyst
Bains, Amreen K.,Kundu, Abhishek,Yadav, Sudha,Adhikari, Debashis
, p. 9051 - 9059 (2019/10/02)
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.
A bifunctional strategy for N-heterocyclic carbene-stabilized iridium complex-catalyzed: N -alkylation of amines with alcohols in aqueous media
Huang, Ming,Li, Yinwu,Liu, Jiahao,Lan, Xiao-Bing,Liu, Yan,Zhao, Cunyuan,Ke, Zhuofeng
supporting information, p. 219 - 224 (2019/01/28)
Through the strategy of combining bifunctional 2-hydroxypyridine and a thermally stable N-heterocyclic carbene ligand, an Ir-catalyzed N-monoalkylation reaction has been developed in aqueous media under base-free conditions. This reaction proceeds smoothly with high yields of various aromatic amines and sulfonamides with a wide range of primary alcohols. Experimental and computational studies revealed a metal-ligand cooperative mechanism and its thermal stability during the bifunctional catalysis in aqueous media.
