5405-15-2Relevant academic research and scientific papers
Copper(i)-catalysed intramolecular hydroarylation-redox cross-dehydrogenative coupling ofN-propargylanilines with phosphites
Li, Guangzhe,Yu, Guo,Wang, Chengdong,Morita, Taiki,Zhang, Xuhai,Nakamura, Hiroyuki
supporting information, p. 113 - 116 (2021/12/29)
Intramolecular hydroarylation-redox cross-dehydrogenative coupling ofN-propargylanilines with phosphite diesters proceeded in the presence of Cu(i)-catalysts (20 mol%) to selectively give 2-phosphono-1,2,3,4-tetrahydroquinolines in good yields with 100% atomic utilization. P-H and two C-H bonds are activated at once and these hydrogen atoms are trapped by a propargylic triple bond in the molecule.
Catalytic Amination of Phenols with Amines
Chen, Kai,Kang, Qi-Kai,Li, Yuntong,Wu, Wen-Qiang,Zhu, Hui,Shi, Hang
supporting information, p. 1144 - 1151 (2022/02/05)
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.
[(PPh3)2NiCl2]-Catalyzed C-N bond formation reaction via borrowing hydrogen strategy: Access to diverse secondary amines and quinolines
Donthireddy,Pandey, Vipin K.,Rit, Arnab
supporting information, p. 6994 - 7001 (2021/06/09)
Commercially available [(PPh3)2NiCl2] was found to be an efficient catalyst for the mono-N-alkylation of (hetero)- A romatic amines, employing alcohols to deliver diverse secondary amines, including the drug intermediates chloropyramine (5b) and mepyramine (5c), in excellent yields (up to 97%) via the borrowing hydrogen strategy. This method shows a superior activity (TON up to 10000) with a broad substrate scope at a low catalyst loading of 1 mol % and a short reaction time. Further, this strategy is also successful in accessing various quinoline derivatives following the acceptorless dehydrogenation pathway.
Biorenewable carbon-supported Ru catalyst for: N -alkylation of amines with alcohols and selective hydrogenation of nitroarenes
Goyal, Vishakha,Narani, Anand,Natte, Kishore,Poddar, Mukesh Kumar,Ray, Anjan,Sarki, Naina,Tripathi, Deependra
, p. 14687 - 14694 (2021/08/23)
Herein, we developed a renewable carbon-supported Ru catalyst (Ru/PNC-700), which was facilely prepared via simple impregnation followed by the pyrolysis process. The prepared Ru/PNC-700 catalyst demonstrated remarkable catalytic activity in terms of conversion and selectivity towards N-alkylation of anilines with benzyl alcohol and chemoselective hydrogenation of aromatic nitro compounds. In addition, local anesthetic pharmaceutical agents (e.g., butamben and benzocaine), including key drug intermediates, were synthesized in excellent yields under mild conditions and in the presence of water as a green solvent. Moreover, the prepared Ru/PNC-700 catalyst could be easily recovered and reused up to five times without any apparent loss in activity and selectivity.
A Tetraarylpyrrole-Based Phosphine Ligand for the Palladium-Catalyzed Amination of Aryl Chlorides
Sai, Masahiro
supporting information, p. 5422 - 5428 (2021/10/08)
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.).
BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
supporting information, p. 5205 - 5211 (2021/07/29)
A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
Sulfated polyborate: A dual catalyst for the reductive amination of aldehydes and ketones by NaBH4
Ganwir, Prerna,Chaturbhuj, Ganesh
, (2021/05/19)
An efficient, quick, and environment-friendly one-pot reductive amination of aldehydes or ketones was developed. In ethanol at 70 °C, a imination catalyzed by sulfated polyborate and further reduced by sodium borohydride yields various amines. The present method has many significant benefits, including a shorter reaction time, excellent yields, and a hassle-free, straightforward experimental process. The reaction has a wide range of applications due to its flexibility, including secondary amine for reductive amination.
Palladium supported on magnesium hydroxyl fluoride: An effective acid catalyst for the hydrogenation of imines and N-heterocycles
Agbossou-Niedercorn, Francine,Corre, Yann,Dongare, Mohan K.,Kemnitz, Erhard,Kokane, Reshma,Michon, Christophe,Umbarkar, Shubhangi B.
supporting information, p. 19572 - 19583 (2021/11/04)
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
Photocatalytic Water-Splitting Coupled with Alkanol Oxidation for Selective N-alkylation Reactions over Carbon Nitride
Xu, Yangsen,Zhang, Zhaofei,Qiu, Chuntian,Chen, Shaoqin,Ling, Xiang,Su, Chenliang
, p. 582 - 589 (2020/12/09)
Photocatalytic water splitting technology (PWST) enables the direct use of water as appealing “liquid hydrogen source” for transfer hydrogenation reactions. Currently, the development of PWST-based transfer hydrogenations is still in an embryonic stage. Previous reports generally centered on the rational utilization of the in situ generated H-source (electrons) for hydrogenations, in which photogenerated holes were quenched by sacrificial reagents. Herein, the fully-utilization of the liquid H-source and holes during water splitting is presented for photo-reductive N-alkylation of nitro-aromatic compounds. In this integrate system, H-species in situ generated from water splitting were designed for nitroarenes reduction to produce amines, while alkanols were oxidized by holes for cascade alkylating of anilines as well as the generated secondary amines. More than 50 examples achieved with a broad range scope validate the universal applicability of this mild and sustainable coupling approach. The synthetic utility of this protocol was further demonstrated by the synthesis of existing pharmaceuticals via selective N-alkylation of amines. This strategy based on the sustainable water splitting technology highlights a significant and promising route for selective synthesis of valuable N-alkylated fine chemicals and pharmaceuticals from nitroarenes and amines with water and alkanols.
Reductive Alkylation of Azides and Nitroarenes with Alcohols: A Selective Route to Mono- And Dialkylated Amines
Borthakur, Ishani,Joshi, Abhisek,Kundu, Sabuj,Maji, Milan
, (2021/12/27)
Herein, we demonstrated an efficient protocol for reductive alkylation of azides/nitro compounds via a borrowing hydrogen (BH) method. By following this protocol, selective mono- and dialkylated amines were obtained under mild and solvent-free conditions. A series of control experiments and deuterium-labeling experiments were performed to understand this catalytic process. Mechanistic studies suggested that the Ir(III)-H was the active intermediate in this reaction. KIE study revealed that the breaking of the C-H bond of alcohol might be the rate-limiting step. Notably, this solvent-free strategy disclosed a high TON of around 5600. Based on kinetic studies and control experiments, a metal-ligand cooperative mechanism was proposed.
