- SYNTHESIS OF CYCLOPROPYLAMINOOXOSULFONIUM SALTS BY THE REACTION OF DIAMINOOXOSULFONIUM YLIDES WITH ALDEHYDES
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The title compounds have been synthesized by the reaction of diaminooxosulfonium methylides with aldehydes as isomeric mixtures in good yields.These ylides reacted with aldehydes to give betaines, which formed unusual four-membered cyclic alkoxyoxosulfonium salts.Another methylide further attacked α-carbon of these salts to afford cyclopropyldiaminooxosulfonium salts.
- Okuma, Kentaro,Nakanishi, Kazuto,Honda, Takumi,Ohta, Hiroshi,Yokomori, Yoshinobu,Sekido, Kiyotane
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- Electronically tuneable orthometalated RuII–NHC complexes as efficient catalysts for C–C and C–N bond formations via borrowing hydrogen strategy
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The catalytic activities of a series of simple and electronically tuneable cyclometalated RuII–NHC complexes (2a–d) were explored in various C–C/N bond formations following the borrowing hydrogen process. Slight modifications in the ligand backbone were noted to tune the activities of these complexes. Among them, the complex 2d featuring a 1,2,4-triazolylidene donor with a 4-NO2–phenyl substituent displayed the highest activity for the coupling of diverse secondary and primary alcohols with a low catalyst loading of 0.01 mol% and a sub-stoichiometric amount of inexpensive KOH base. The efficacy of this simple system was further showcased in the challenging one-pot unsymmetrical double alkylation of secondary alcohols using different primary alcohols. Moreover, the complex 2d also effectively catalyses the selective mono-N-methylation of various aromatic and aliphatic primary amines using methanol to deliver a range of N-methyl amines. Mechanistically, the β-alkylation reaction follows a borrowing hydrogen pathway which was established by the deuterium labelling experiment in combination with various control experiments. Intriguingly, in situ1H NMR and ESI-MS analyses evidently suggested the involvement of a Ru–H species in the catalytic cycle and further, the kinetic studies revealed a first order dependence of the reaction rate on the catalyst as well as the alcohol concentrations.
- Illam, Praseetha Mathoor,Rit, Arnab
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- Reusable Co-nanoparticles for general and selectiveN-alkylation of amines and ammonia with alcohols
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A general cobalt-catalyzedN-alkylation of amines with alcohols by borrowing hydrogen methodology to prepare different kinds of amines is reported. The optimal catalyst for this transformation is prepared by pyrolysis of a specific templated material, which is generatedin situby mixing cobalt salts, nitrogen ligands and colloidal silica, and subsequent removal of silica. Applying this novel Co-nanoparticle-based material, >100 primary, secondary, and tertiary amines includingN-methylamines and selected drug molecules were conveniently prepared starting from inexpensive and easily accessible alcohols and amines or ammonia.
- Beller, Matthias,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kadam, Ravishankar G.,Li, Xinmin,Ma, Zhuang,Petr, Martin,Zbo?il, Radek,Zhou, Bei
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p. 111 - 117
(2022/01/06)
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- Photoinduced Hydroarylation and Cyclization of Alkenes with Luminescent Platinum(II) Complexes
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Photoinduced hydroarylation of alkenes is an appealing synthetic strategy for arene functionalization. Herein, we demonstrated that aryl radicals generated from electron-deficient aryl chlorides/bromides could be trapped by an array of terminal/internal aryl alkenes in the presence of [Pt(O^N^C^N)] under visible-light (410 nm) irradiation, affording anti-Markovnikov hydroarylated compounds in up to 95 % yield. Besides, a protocol for [Pt(O^N^C^N)]-catalyzed intramolecular photocyclization of acrylanilides to give structurally diverse 3,4-dihydroquinolinones has been developed.
- Cheng, Hanchao,Lam, Tsz-Lung,Liu, Yungen,Tang, Zhou,Che, Chi-Ming
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supporting information
p. 1383 - 1389
(2020/11/30)
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- Novel hybrid conjugates with dual estrogen receptor α degradation and histone deacetylase inhibitory activities for breast cancer therapy
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Hormone therapy targeting estrogen receptors is widely used clinically for the treatment of breast cancer, such as tamoxifen, but most of them are partial agonists, which can cause serious side effects after long-term use. The use of selective estrogen receptor down-regulators (SERDs) may be an effective alternative to breast cancer therapy by directly degrading ERα protein to shut down ERα signaling. However, the solely clinically used SERD fulvestrant, is low orally bioavailable and requires intravenous injection, which severely limits its clinical application. On the other hand, double- or multi-target conjugates, which are able to synergize antitumor activity by different pathways, thus may enhance therapeutic effect in comparison with single targeted therapy. In this study, we designed and synthesized a series of novel dual-functional conjugates targeting both ERα degradation and histone deacetylase inhibiton by combining a privileged SERD skeleton 7-oxabicyclo[2.2.1]heptane sulfonamide (OBHSA) with a histone deacetylase inhibitor side chain. We found that substituents on both the sulfonamide nitrogen and phenyl group of OBHSA unit had significant effect on biological activities. Among them, conjugate 16i with N-methyl and naphthyl groups exhibited potent antiproliferative activity against MCF-7 cells, and excellent ERα degradation activity and HDACs inhibitory ability. A further molecular docking study indicated the interaction patterns of these conjugates with ERα, which may provide guidance to design novel SERDs or PROTAC-like SERDs for breast cancer therapy.
- Zhao, Chenxi,Tang, Chu,Li, Changhao,Ning, Wentao,Hu, Zhiye,Xin, Lilan,Zhou, Hai-Bing,Huang, Jian
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- Nanosized CdS as a Reusable Photocatalyst: The Study of Different Reaction Pathways between Tertiary Amines and Aryl Sulfonyl Chlorides through Visible-Light-Induced N-Dealkylation and C-H Activation Processes
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It has been found that the final products of the reaction of sulfonyl chlorides and tertiary amines in the presence of cadmium sulfide nanoparticles under visible light irradiation are highly dependent on the applied reaction conditions. Interestingly, with the change of a reaction condition, different pathways were conducted (visible-light-induced N-dealkylation or sp3 and sp2 C-H activation) that lead to different products such as secondary amines and various sulfonyl compounds. Remarkably, all of these reactions were performed under visible light irradiation and an air atmosphere without any additive or oxidant in benign solvents or under solvent-free conditions. During this study, the CdS nanoparticles as affordable, heterogeneous, and recyclable photocatalysts were designed, successfully synthesized, and fully characterized and applied for these protocols. During these studies, intermediates resulting from the oxidation of tertiary amines are trapped during the photoinduced electron transfer (PET) process. The reaction was carried out efficiently with a variety of substrates to give the corresponding products at relatively short times in good to excellent yields in parallel with the use of the visible light irradiation as a renewable energy source. Most of these processes are novel or are superior in terms of cost-effectiveness, safety, and simplicity to published reports.
- Firoozi, Somayeh,Hosseini-Sarvari, Mona
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p. 2117 - 2134
(2021/02/05)
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- A nonheme peroxo-diiron(iii) complex exhibiting both nucleophilic and electrophilic oxidation of organic substrates
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The complex [FeIII2(μ-O2)(L3)4(S)2]4+(L3= 2-(4-thiazolyl)benzimidazole, S = solvent) forms upon reaction of [FeII(L3)2] with H2O2and is a functional model of peroxo-diiron intermediates invoked during the catalytic cycle of oxidoreductases. The spectroscopic properties of the complex are in line with those of complexes formed with N-donor ligands. [FeIII2(μ-O2)(L3)4(S)2]4+shows both nucleophilic (aldehydes) and electrophilic (phenol,N,N-dimethylanilines) oxidative reactivity and unusually also electron transfer oxidation.
- Browne, Wesley R.,Giorgi, Michel,Kaizer, József,T?r?k, Patrik,Unjaroen, Duenpen,Viktória Csendes, Flóra
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supporting information
p. 7181 - 7185
(2021/06/11)
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- CO2-tuned highly selective reduction of formamides to the corresponding methylamines
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We herein describe an efficient, CO2-tuned and highly selective C-O bond cleavage of N-methylated formanilides. With easy-to-handle and commercially available NaBH4 as the reductant, a variety of formanilides could be turned into the desired tertiary amines in moderate to excellent yields. The role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments.
- Chao, Jianbin,Guo, Zhiqiang,Pang, Tengfei,Wei, Xuehong,Xi, Chanjuan,Yan, Leilei
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supporting information
p. 7534 - 7538
(2021/10/12)
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- Method for realizing N-alkylation by using alcohols as carbon source under photocatalysis
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The invention discloses a method for realizing N-alkylation by using alcohols as a carbon source under photocatalysis, and belongs to the technical field of catalytic synthesis. Alcohol, a substrate raw material and a catalyst are placed in a reaction device, ultraviolet and/or visible light irradiation is carried out in an inert atmosphere, after the irradiation is finished, solid-liquid separation is carried out to remove the catalyst, and an N-alkylation product can be obtained through extraction, distillation and purification, wherein the substrate raw material comprises any one of an amine compound, an aromatic nitro compound or an aromatic nitrile compound, the alcohol comprises any one or more of soluble primary alcohols, and the catalyst is metal oxide/titanium dioxide or metal sulfide/titanium dioxide. The method is simple and easy to operate, can be used for efficient photocatalysis one-pot multi-step hydrogenation N-alkylation reaction, and is mild in reaction condition, high in chemical selectivity of N-alkylamine, good in catalyst stability and easy to recycle.
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Paragraph 0048-0057
(2021/03/13)
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- Additive-freeN-methylation of amines with methanol over supported iridium catalyst
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An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
- Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
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p. 3364 - 3375
(2021/06/06)
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- Ru-Catalyzed Selective Catalytic Methylation and Methylenation Reaction Employing Methanol as the C1 Source
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Methanol can be employed as a green and sustainable methylating agent to form C-C and C-N bonds via borrowing hydrogen (BH) methodology. Herein we explored the activity of the acridine-derived SNS-Ru pincer for the activation of methanol to apply it as a C1 building block in different reactions. Our catalytic system shows great success toward the β-C(sp3)-methylation reaction of 2-phenylethanols to provide good to excellent yields of the methylated products. We investigated the mechanistic details, kinetic progress, and temperature-dependent product distribution, which revealed the slow and steady generation of in situ formed aldehyde, is the key factor to get the higher yield of the β-methylated product. To establish the environmental benefit of this reaction, green chemistry metrics are calculated. Furthermore, dimerization of 2-naphthol via methylene linkage and formation of N-methylation of amine are also described in this study, which offers a wide range of substrate scope with a good to excellent yield.
- Biswas, Nandita,Srimani, Dipankar
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p. 10544 - 10554
(2021/07/31)
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- N-Methylation of Amines with Methanol in the Presence of Carbonate Salt Catalyzed by a Metal-Ligand Bifunctional Ruthenium Catalyst [(p-cymene)Ru(2,2′-bpyO)(H2O)]
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A ruthenium complex [(p-cymene)Ru(2,2′-bpyO)(H2O)] was found to be a general and efficient catalyst for the N-methylation of amines with methanol in the presence of carbonate salt. Moreover, a series of sensitive substituents, such as nitro, ester, cyano, and vinyl groups, were tolerated under present conditions. It was confirmed that OH units in the ligand are crucial for the catalytic activity. Notably, this research exhibited the potential of metal-ligand bifunctional ruthenium catalysts for the hydrogen autotransfer process.
- Liu, Peng,Tung, Nguyen Thanh,Xu, Xiangchao,Yang, Jiazhi,Li, Feng
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p. 2621 - 2631
(2021/02/27)
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- Recyclable covalent triazine framework-supported iridium catalyst for the N-methylation of amines with methanol in the presence of carbonate
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An iridium complex Cp*Ir@CTF, which is synthesized by the coordinative immobilization of [Cp*IrCl2]2 on a functionalized covalent triazine framework (CTF), was found to be a general and highly efficient catalyst for the N-methylation of amines with methanol in the presence of carbonate. Under environmentally benign conditions, a variety of desirable products were obtained in high yields with complete selectivities and functional group friendliness. Furthermore, the synthesized catalyst could be recycled by simple filtration without obvious loss of catalytic activity after sixth cycle. Notably, this research exhibited the potential of covalent triazine framework-supported transition metal catalysts for hydrogen autotransfer process.
- Liu, Peng,Yang, Jiazhi,Ai, Yao,Hao, Shushu,Chen, Xiaozhong,Li, Feng
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p. 281 - 290
(2021/03/26)
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- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost-competitive method with the use of methanol as both C1 synthon and H2 source for selective N-methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand-free catalyst. This readily available catalyst tolerates various amines comprising electron-deficient and electron-donating groups and allows them to transform into corresponding N-methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late-stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N-methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N-methylated amines using MeOH under H2-free conditions including transfer hydrogenation of nitroarenes-to-anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one-shot selective and green syntheses of 1-methylbenzimidazole using ortho-phenylenediamine (OPDA) and methanol as coupling partners.
- Sarki, Naina,Goyal, Vishakha,Tyagi, Nitin Kumar,Puttaswamy,Narani, Anand,Ray, Anjan,Natte, Kishore
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p. 1722 - 1729
(2021/04/19)
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- Effect of the ancillary ligand in N-heterocyclic carbene iridium(III) catalyzed N-alkylation of amines with alcohols
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A series of air-stable N-heterocyclic carbene (NHC) Ir(III) complexes (Ir1-6), bearing various combinations of chlorine, pyridine and NHC ligands, were assayed for the N-alkylation of amines with alcohols. It was found that Ir3, with two monodentate 1,3-bis-methyl-imidazolylidene (IMe) ligands, emerged as the most active complex. A large variety of amines and primary alcohols were efficiently converted into mono-N-alkylated amines in 53–96% yields. As a special highlight, for the challenging MeOH, selective N-monomethylation could be achieved using KOH as a base under an air atmosphere. Moreover, this catalytic system was successfully applied to the gram-scale synthesis of some valuable compounds.
- Feng, Xinshu,Huang, Ming
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- Efficient methylation of anilines with methanol catalysed by cyclometalated ruthenium complexes
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Cyclometalated ruthenium complexes4-10allow the effective methylation of anilines with methanol to selectively giveN-methylanilines. This hydrogen autotransfer procedure proceeds under mild conditions (60 °C) in a practical manner (NaOH as base). Mechanistic investigations suggest an active homogenous ruthenium complex and β-hydride elimination of methanol as the rate determining step.
- Piehl, Patrick,Amuso, Roberta,Spannenberg, Anke,Gabriele, Bartolo,Neumann, Helfried,Beller, Matthias
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p. 2512 - 2517
(2021/04/22)
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- Aminomethylation of Aryl Bromides by Nickel-Catalyzed Electrochemical Redox Neutral Cross Coupling
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We develop an electrochemical nickel-catalyzed aminomethylation of aryl bromides under mild conditions. The convergent paired electrolysis makes full use of anode and cathode processes, free of a terminal oxidant, a sacrificial anode, a metal reductant, and a prefunctionalized radical precursor. In addition, this method exhibits wide functional group tolerance (63 examples), including some sensitive substituents and aromatic heterocycles. This redox neutral cross coupling provides a more environmentally friendly and synthetic practical protocol for forging C(sp2)–C(sp3) bonds.
- Ma, Yueyue,Hong, Jufei,Yao, Xiantong,Liu, Chengyu,Zhang, Ling,Fu, Youtian,Sun, Maolin,Cheng, Ruihua,Li, Zhong,Ye, Jinxing
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supporting information
p. 9387 - 9392
(2021/12/17)
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- A Metal-Free Direct Arene C?H Amination
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The synthesis of aryl amines via the formation of a C?N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal-catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal-free arene C?H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen-bridged complex with a “Sandwich-like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule. (Figure presented.).
- Wang, Tao,Hoffmann, Marvin,Dreuw, Andreas,Hasagi?, Edina,Hu, Chao,Stein, Philipp M.,Witzel, Sina,Shi, Hongwei,Yang, Yangyang,Rudolph, Matthias,Stuck, Fabian,Rominger, Frank,Kerscher, Marion,Comba, Peter,Hashmi, A. Stephen K.
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supporting information
p. 2783 - 2795
(2021/04/05)
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- Synthesis of N-Alkyl Anilines from Arenes via Iron-Promoted Aromatic C-H Amination
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We report both an intermolecular C-H amination of arenes to access N-methylanilines and an intramolecular variant for the synthesis of tetrahydroquinolines. A newly developed, highly electrophilic aminating reagent was key for the direct synthesis of unprotected N-methylanilines from simple arenes. The reactions display a broad functional group tolerance and employ catalytic amounts of a benign iron salt under mild reaction conditions.
- Falk, Eric,Gasser, Valentina C. M.,Morandi, Bill
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supporting information
p. 1422 - 1426
(2021/03/08)
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- Photocatalytic Water-Splitting Coupled with Alkanol Oxidation for Selective N-alkylation Reactions over Carbon Nitride
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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.
- Xu, Yangsen,Zhang, Zhaofei,Qiu, Chuntian,Chen, Shaoqin,Ling, Xiang,Su, Chenliang
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p. 582 - 589
(2020/12/09)
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- Biobased Spiroimides from Itaconic Acid and Formamides: Molecular Targets for a Novel Synthetic Application of Renewable Chemicals
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Spiroimides exhibit a wide range of biological activities, such as anticonvulsant, antiarrhythmic, and antihyperglycemic activities. Herein, a novel synthetic application of renewable chemicals, itaconic acid and formamides, is described. Proper exploitation of the reactivity of itaconic acid and formamide allows for the development of an efficient synthetic approach for the production of several new biobased spiroimides, spiro[dihydroquinolin-2-one-succinimides] and spiro[indolin-2-one-glutarimides], in excellent overall yields (up to 98%).
- Hornink, Milene Macedo,Lopes, Alice Uva,Andrade, Leandro Helgueira
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supporting information
p. 296 - 308
(2020/11/09)
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- Selective Pd-catalyzed monoarylation of small primary alkyl amines through backbone-modification in ylide-functionalized phosphines (YPhos)
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Ylide-substituted phosphines have been shown to be excellent ligands for C-N coupling reactions under mild reaction conditions. Here we report studies on the impact of the steric demand of the substituent in the ylide-backbone on the catalytic activity. Two new YPhos ligands with bulky ortho-tolyl (pinkYPhos) and mesityl (mesYPhos) substituents were synthesized, which are slightly more sterically demanding than their phenyl analogue but considerably less flexible. This change in the ligand design leads to higher selectivities and yields in the arylation of small primary amines compared to previously reported YPhos ligands. Even MeNH2 and EtNH2 could be coupled at room temperature with a series of aryl chlorides in high yields.
- Rodstein, Ilja,Prendes, Daniel Sowa,Wickert, Leon,Paa?en, Maurice,Gessner, Viktoria H.
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p. 14674 - 14683
(2020/12/29)
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- Esterification of Tertiary Amides: Remarkable Additive Effects of Potassium Alkoxides for Generating Hetero Manganese–Potassium Dinuclear Active Species
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A catalyst system of mononuclear manganese precursor 3 combined with potassium alkoxide served as a superior catalyst compared with our previously reported manganese homodinuclear catalyst 2 a for esterification of not only tertiary aryl amides, but also tertiary aliphatic amides. On the basis of stoichiometric reactions of 3 and potassium alkoxide salt, kinetic studies, and density functional theory (DFT) calculations, we clarified a plausible reaction mechanism in which in situ generated manganese–potassium heterodinuclear species cooperatively activates the carbonyl moiety of the amide and the OH moiety of the alcohols. We also revealed details of the reaction mechanism of our previous manganese homodinuclear system 2 a, and we found that the activation free energy (ΔG≠) for the manganese–potassium heterodinuclear complex catalyzed esterification of amides is lower than that for the manganese homodinuclear system, which was consistent with the experimental results. We further applied our catalyst system to deprotect the acetyl moiety of primary and secondary amines.
- Akiyama, Shoko,Himo, Fahmi,Hirai, Takahiro,Katayama, Shoichiro,Kato, Daiki,Mai, Binh Khanh,Mashima, Kazushi,Nagae, Haruki
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- Transition-Metal-Free and Visible-Light-Mediated Desulfonylation and Dehalogenation Reactions: Hantzsch Ester Anion as Electron and Hydrogen Atom Donor
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Novel approaches for N- and O-desulfonylation under room temperature (rt) and transition-metal-free conditions have been developed. The first methodology involves the transformation of a variety of N-sulfonyl heterocycles and phenyl benzenesulfonates to the corresponding desulfonylated products in good to excellent yields using only KOtBu in dimethyl sulfoxide (DMSO) at rt. Alternately, a visible light method has been used for deprotection of N-methyl-N-arylsulfonamides with Hantzsch ester (HE) anion serving as the visible-light-absorbing reagent and electron and hydrogen atom donor to promote the desulfonylation reaction. The HE anion can be easily prepared in situ by reaction of the corresponding HE with KOtBu in DMSO at rt. Both protocols were further explored in terms of synthetic scope as well as mechanistic aspects to rationalize key features of desulfonylation processes. Furthermore, the HE anion induces reductive dehalogenation reaction of aryl halides under visible light irradiation.
- Heredia, Micaela D.,Guerra, Walter D.,Barolo, Silvia M.,Fornasier, Santiago J.,Rossi, Roberto A.,Budén, Mariá E.
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p. 13481 - 13494
(2020/12/15)
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- Highly Efficient Binuclear Copper-catalyzed Oxidation of N,N-Dimethylanilines with O2
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A binuclear copper-salicylate complex, [Cu(Sal)2(NCMe)]2 (Sal=salicylate), was found to be an active catalyst for the oxidation of N,N-dimethylanilines by O2, affording the corresponding N-methyl-N-phenylformamides as major products. The reactions were carried out with a O2 balloon and the S/C (substrate/catalyst ratio) of the model reaction could be up to 1×105, providing a practical and highly efficient catalytic protocol for accessing N-methyl-N-phenylformamides.
- Liu, Yuxia,Yan, Yonggang,Xue, Dong,Wang, Zhongfu,Xiao, Jianliang,Wang, Chao
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p. 2221 - 2225
(2020/03/23)
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- Synthesis of: N -methylated amines from acyl azides using methanol
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The transformation of acyl azide derivatives into N-methylamines was developed using methanol as the C1 source via the one-pot Curtius rearrangement and borrowing hydrogen methodology. Following this protocol, various functionalised N-methylated amines were synthesized using the (NNN)Ru(ii) complex from carboxylic acids via an acyl azide intermediate. Several kinetic studies and DFT calculations were carried out to support the mechanism and also to determine the role of the Ru(ii) complex and base in this transformation.
- Chakrabarti, Kaushik,Dutta, Kuheli,Kundu, Sabuj
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p. 5891 - 5896
(2020/08/21)
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- N-Methylation of Amines with Methanol in Aqueous Solution Catalyzed by a Water-Soluble Metal-Ligand Bifunctional Dinuclear Iridium Catalyst
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The N-methylation of amines with methanol in aqueous solution was proposed and accomplished by using a water-soluble metal-ligand bifunctional dinuclear iridium catalyst. In the presence of [(Cp*IrCl)2(thbpym)][Cl]2 (1 mol %), a range of desirable products were obtained in high yields under environmentally benign conditions. Notably, this research exhibited the potential of transition metal-catalyzed activation of methanol as a C1 source for the construction of the C-N bond in aqueous solution.
- Han, Xingyou,Li, Feng,Liu, Peng,Meng, Chong,Tung, Nguyen Thanh
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p. 5815 - 5824
(2020/05/26)
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- METHOD FOR PRODUCING N-METHYL-P-TOLUIDINE FOR USE AS AN ADDITIVE FOR AVIATION GASOLINE
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The invention relates to novel methods for preparing N-methyl-p-toluidine for the use thereof as additive for aviation fuel, and to specific catalysts for these methods.
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Paragraph 0075-0084
(2020/06/07)
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- Iridium-Catalysed Reductive Deoxygenation of Ketones with Formic Acid as Traceless Hydride Donor
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An iridium-catalysed deoxygenation of ketones and aldehydes is achieved, with formic acid as hydride donor and water as co-solvent. At low catalyst loading, a number of 4-(N,N-disubstituted amino) aryl ketones are readily deoxygenated in excellent yields and chemoselectivity. Numerous functional groups, especially phenolic and alcoholic hydroxyls, secondary amine, carboxylic acid, and alkyl chloride, are well tolerable. Geminally dideuterated alkanes are obtained with up to 90% D incorporation, when DCO2D and D2O are used in place of their hydrogenative counterparts. The activating 4-(N,N-disubstituted amino)aryl groups have been demonstrated to undergo a variety of useful transformations. The deoxygenative deuterations have been used to prepare a deuterated drug molecule Chlorambucil-4,4-d2. (Figure presented.).
- Yang, Zhiheng,Zhu, Xueya,Yang, Shiyi,Cheng, Weiyan,Zhang, Xiaojian,Yang, Zhanhui
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supporting information
p. 5496 - 5505
(2020/10/22)
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- Selective N -monomethylation of primary anilines with the controllable installation of N -CH2D, N -CHD2, and N -CD3units
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The selective N-monomethylation of primary anilines was realized by the use of the Me3N-BH3/N,N-dimethylformamide (DMF) system as the methyl source. This method also allows for the controllable introduction of N-CH2D, N-CHD2, and N-CD3 units with high lev
- Meng, Jing,Wang, Yi-Feng,Wang, Zhijuan,Xia, Hui-Min,Xu, Ai-Qing,Zhang, Feng-Lian
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supporting information
p. 4922 - 4926
(2020/07/30)
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- Catalyst-Free Electrosynthesis of Benzimidazolones through Intramolecular Oxidative C?N Coupling
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The electrochemical synthesis of N, N’-disubstituted benzimidazolones from ureas through an intramolecular anodic dehydrogenative N?H/C?H coupling has been developed. The reaction undergoes under the undivided electrolysis conditions and obviates the need for any catalysts and chemical oxidants. (Figure presented.).
- Li, Jiang-Sheng,Yang, Pan-Pan,Xie, Xin-Yun,Jiang, Si,Tao, Li,Li, Zhi-Wei,Lu, Cui-Hong,Liu, Wei-Dong
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supporting information
p. 1977 - 1981
(2020/04/20)
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- EffectiveN-methylation of nitroarenes with methanol catalyzed by a functionalized NHC-based iridium catalyst: a green approach toN-methyl amines
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Compound [IrBr(CO)2(κC-tBuImCH2PyCH2OMe)] featuring a flexible pyridine/OMe functionalized NHC ligand κ1C coordinated efficiently catalyzes the selectiveN-monomethylation of nitroarenes using methanol as both the reducing agent and the C1 source. A range of functionalized nitroarenes including heterocyclic or sterically hindered derivatives have been efficiently converted to the correspondingN-monomethyl amines in good yields at low catalyst loadings using sub-stoichiometric amounts of Cs2CO3as a base. Mechanistic investigations support a borrowing-hydrogen mechanism in which methanol acts as the hydrogen source and methylating agent. Further, the hydrogen transfer reduction of nitrobenzene to aniline under optimized reaction conditions should proceed through a direct mechanism involving nitrosobenzene andN-phenylhydroxylamine intermediates.
- González-Lainez, Miguel,Jiménez, M. Victoria,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.
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p. 3458 - 3467
(2020/06/17)
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- Selective mono-N-methylation of nitroarenes with methanol catalyzed by atomically dispersed NHC-Ir solid assemblies
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A series of N-heterocyclic carbene-iridium (NHC-Ir) coordination assemblies based on bis-pyrenoimidazolium salts are prepared, and shown to function as efficient solid molecular catalysts in selective mono-N-methylation of nitroarenes with methanol under mild conditions. The atomically dispersed active Ir(I) centers and the large π-conjugation rings endow the solid catalysts with an exceptionally high activity and selectivity for a broad substrate scope. Such solid NHC-Ir coordination assemblies are robust, which can be easily recovered and reused more than 10 runs without significant loss of their catalytic activity and selectivity. When combined with a subsequent formylation using the same solid catalysts under ambient conditions, this novel protocol can afford diverse formamides in excellent yields, further highlighting the applicability of the present solid catalysts for an efficient diversification of nitroarenes to a broad number of functional amines.
- Chen, Jiangbo,Chen, Zhe-Ning,Tu, Tao,Wang, Jiaquan,Wen, Daheng,Wu, Jiajie,Xu, Xin,Zheng, Qingshu
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p. 337 - 344
(2020/07/03)
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- Manganese-Catalyzed One-Pot Conversion of Nitroarenes into N-Methylarylamines Using Methanol
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A manganese-catalyzed one-pot conversion of nitroarenes into N-methylarylamines has been developed. This transfer hydrogenation method employs a well-defined bench stable Mn PN3P pincer precatalyst in combination with methanol as both the reductant and the C1 source. A selection of commercially available nitroarenes was converted into N-methylarylamines in synthetically useful yields.
- Mast, Nicolas,Morrill, Louis C.,Reed-Berendt, Benjamin G.
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supporting information
(2020/03/03)
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- Methoxycarbonylation of Alkyl-, Cycloalkyl-, and Arylamines with Dimethyl Carbonate in the Presence of Binder-Free Zeolite
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Abstract: Methyl N-alkyl-, N-cycloalkyl-, and N-arylcarbamates were synthesized by reaction of the correspondingamines with dimethyl carbonate in the presence of binder-free FeHY zeolite. Theoptimal conditions (reactant ratio, amount of the catalyst, temperature,reaction time) were found to afford the target products with high yields.
- Khazipova, A. N.,Khusnutdinov, R. I.,Mayakova, Yu. Yu.,Shchadneva, N. A.
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p. 1228 - 1235
(2020/10/02)
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- Electrosynthesis of Dihydropyrano[4,3-b]indoles Based on a Double Oxidative [3+3] Cycloaddition
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Oxidative [3+3] cycloadditions offer an efficient route for six-membered-ring formation. This approach has been realized based on an electrochemical oxidative coupling of indoles/enamines with active methylene compounds followed by tandem 6π-electrocyclization leading to the synthesis of dihydropyrano[4,3-b]indoles and 2,3-dihydrofurans. The radical–radical cross-coupling of the radical species generated by anodic oxidation combined with the cathodic generation of the base from O2 allows for mild reaction conditions for the synthesis of structurally complex heterocycles.
- Choi, Subin,Park, Cheol-Min,Park, Jinhwi,Sim, Jeongwoo,Yu, Eunsoo
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supporting information
p. 11886 - 11891
(2020/05/22)
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- Binuclear rhodium complex containing ortho-carborane structure and preparation and application thereof
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The invention relates to a binuclear rhodium complex containing an ortho-carborane structure and preparation and application thereof. The preparation method of the rhodium complex comprises the following steps: 1) adding an n-BuLi solution into an ortho-carborane solution, and then reacting for 30-60 min at room temperature; 2) adding selenium and reacting for 1-2h at room temperature; 3) adding [Cp*RhCl2]2, reacting at room temperature for 3-6h, and performing post-treating to obtain the rhodium complex; and the rhodium complex is used to catalyze arylamine N-methylation reaction to prepare arylamine N-methylated derivatives. Compared with the prior art, the preparation method of the binuclear semi-sandwich rhodium complex containing the ortho-carborane structure is simple and green, has excellent selectivity and higher yield, and the prepared rhodium complex has higher catalytic activity at room temperature, can be used for catalyzing aromatic amine N-methylation reaction to prepare the aromatic amine N-methylation derivatives, has high catalytic reaction yield, and has wide industrial application prospect.
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-
Paragraph 0039-0042
(2019/10/01)
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- Hydrogenation and: N-Alkylation of anilines and imines via transfer hydrogenation with homogeneous nickel compounds
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The nickel-catalyzed N-Alkylation of a variety of arylamines via transfer hydrogenation in the absence of pressurized hydrogen and basic or acidic additives was achieved in a tandem reaction. This process was further extended to the CN bond reduction and N-Alkylation of a variety of imines with ethanol, the latter acting as a hydrogen and acetaldehyde source, which allowed for the reduction and subsequent condensation to yield the corresponding N-Alkylated products.
- Benitez-Medina, G. Eliad,García, Juventino J.
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p. 17579 - 17587
(2019/12/23)
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- Catalytic and stoichiometric oxidation of N,N-dimethylanilines mediated by nonheme oxoiron(IV) complex with tetrapyridyl ligand
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Nonheme iron(II) complex, [(N4Py*)FeII(CH3CN)](ClO4)2 (1) with pentadentate tetrapyridyl ligand (N4Py* = N,N-bis(2-pyridylmethyl)-1,2-di(2-pyridyl)ethylamine) has been shown to catalyze the oxidation of N,N-dimethylaniline (DMA) with H2O2, tert-butyl hydroperoxide (TBHP), peracetic acid (PAA), meta-chloroperoxybenzoic acid (mCPBA) and PhIO resulting N-methylaniline (MA) as the predominant product with N-methylformanilide (MFA) as a result of a free-radical chain process. The product composition (MA/MFA) is remarkably influenced by the electron density on the substrate, especially in the 1/mCPBA system, and by the co-oxidants used. No formation of MFA occurred when the oxidation of DMA was carried out in the presence of 1 with PhIO as co-oxidants under argon. Based on spectral investigation (UV–Vis) of reaction systems above, oxoiron(IV) intermediate, [FeIV(N4Py*)(O)]2+ (2) has been suggested to be the key active species of the N-dealkylation reaction in all catalytic systems. The shift in the λmax value of the oxoiron(IV) species in the presence of DMA from 705 to 750 nm, and the new intense absorption in the range of 5–600 nm indicates a complexation and charge-transfer (CT) type interactions between the oxidant and substrate. The stoichiometric oxidation of various N,N-dimethylaniline derivatives with 2 provided clear evidence (Hammett correlation with ρ = ?1.99, and the large negative slope (?4.1) from the logkobs versus Eoox (DMAs) plot) for the rate-determining electron transfer (ET) followed by a proton transfer (PT) process.
- Lakk-Bogáth, Dóra,Kripli, Balázs,Meena, Bashdar I.,Speier, Gábor,Kaizer, József
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p. 169 - 175
(2019/05/29)
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- Iron-Catalyzed Regioselective α-C-H Alkylation of N-Methylanilines: Cross-Dehydrogenative Coupling between Unactivated C(sp3)-H and C(sp3)-H Bonds via a Radical Process
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The iron-catalyzed α-C-H alkylation of N-methylanilines without any directing group by cross-dehydrogenative coupling between unactivated C(sp3)-H and C(sp3)-H bonds has been established for the first time, which provides a good complement to C(sp3)-H activation reactions and expands the field of Fe-catalyzed C-H functionalizations. Many different C(sp3)-H bonds in cyclic alkanes, cyclic ethers, and toluene derivatives can be used as coupling partners. Mechanistic investigations including the radical reaction process, the main role of various reagents, and the kinetic isotope effect experiment were also described.
- Li, Ze-Lin,Sun, Kang-Kang,Wu, Peng-Yu,Cai, Chun
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p. 6830 - 6839
(2019/06/14)
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- Highly selective hydrogenation of amides catalysed by a molybdenum pincer complex: Scope and mechanism
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A series of molybdenum pincer complexes has been shown for the first time to be active in the catalytic hydrogenation of amides. Among the tested catalysts, Mo-1a proved to be particularly well suited for the selective C-N hydrogenolysis of N-methylated formanilides. Notably, high chemoselectivity was observed in the presence of certain reducible groups including even other amides. The general catalytic performance as well as selectivity issues could be rationalized taking an anionic Mo(0) as the active species. The interplay between the amide CO reduction and the catalyst poisoning by primary amides accounts for the selective hydrogenation of N-methylated formanilides. The catalyst resting state was found to be a Mo-alkoxo complex formed by reaction with the alcohol product. This species plays two opposed roles-it facilitates the protolytic cleavage of the C-N bond but it encumbers the activation of hydrogen.
- Leischner, Thomas,Artús Suarez, Lluis,Spannenberg, Anke,Junge, Kathrin,Nova, Ainara,Beller, Matthias
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p. 10566 - 10576
(2019/12/02)
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- Palladacycle-Phosphine Catalyzed Methylation of Amines and Ketones Using Methanol
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Methylation of amines and ketones with palladacycle precatalyst has been performed using methanol as an environmentally benign reagent. Various ketones and amines undergo methylation reaction to yield monomethylated amines or ketones in moderate to good isolated yields. Moreover, this protocol was tested for the chemoselective methylation of 4-aminobenzenesulfonamide. The scope of the reaction was further extended to the deuteromethylation of ketones.
- Mamidala, Ramesh,Biswal, Priyabrata,Subramani, M. Siva,Samser, Shaikh,Venkatasubbaiah, Krishnan
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p. 10472 - 10480
(2019/08/20)
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- N-Methylation of amines and nitroarenes with methanol using heterogeneous platinum catalysts
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We report herein the selective N-methylation of amines and nitroarenes with methanol under basic conditions using carbon-supported Pt nanoparticles (Pt/C) as a heterogeneous catalyst. This method is widely applicable to four types of N-methylation reactions: (1) N,N-dimethylation of aliphatic amines under N2, (2) N-monomethylation of aliphatic amines under 40 bar H2, (3) N-monomethylation of aromatic amines under N2, and (4) tandem synthesis of N-methyl anilines from nitroarenes and methanol under 2 bar H2. All these reactions under the same catalytic system showed high yields of the corresponding methylamines for a wide range of substrates, high turnover number (TON), and good catalyst reusability. Mechanistic studies suggested that the reaction proceeded via a borrowing hydrogen methodology. Kinetic results combined with density functional theory (DFT) calculations revealed that the high performance of Pt/C was ascribed to the moderate metal–hydrogen bond strength of Pt.
- Jamil, Md.A.R.,Touchy, Abeda S.,Rashed, Md. Nurnobi,Ting, Kah Wei,Siddiki, S.M.A. Hakim,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-ichi
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- N–Alkylation of Amines Catalyzed by a Ruthenium–Pincer Complex in the Presence of in situ Generated Sodium Alkoxide
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We report the use of ruthenium–NNN-pincer complexes of the type (R2NNN)RuCl2(PPh3) (R = tBu, iPr, Cy and Ph) for the catalytic N-alkylation of primary amines under solvent-free conditions. For the first time, the base that is required to promote these reactions is generated in situ from the alcohol by the use of sodium. The resulting sodium alkoxide regenerates the alcohol substrate while acting as the water scavenger thus mitigating the need of an additional base. Among the catalysts screened, (tBu2NNN)RuCl2(PPh3) (0.02 mol-%) gives very high turnovers and good yields at 140 °C. The (tBu2NNN)RuCl2(PPh3) catalyzed N-alkylation tolerates a variety of amine and alcohol substrates. While excellent turnover (29000) was obtained for the (tBu2NNN)RuCl2(PPh3) (0.002 mol-%) catalyzed alkylation of aniline with cyclohexyl methanol, the turnovers obtained in the corresponding catalytic methylation of p-anisidine was also very high (12000). The (tBu2NNN)RuCl2(PPh3) catalyzed reactions have also been accomplished under open-vessel conditions resulting in a net dehydrogenative coupling reaction. This protocol has been used to transform benzene-1,2-diamines to benzimidazoles with high productivity (12000 turnovers). DFT studies indicate that while β-hydride elimination is rate-determining (RDTS: 24.31 kcal/mol) for the alcohol dehydrogenation segment which is endothermic, insertion of the imine is rate-determining (RDTS: 11.26 kcal/mol) for its hydrogenation that is exothermic.
- Das, Kanu,Nandi, Pran Gobinda,Islam, Khadimul,Srivastava, Hemant Kumar,Kumar, Akshai
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p. 6855 - 6866
(2019/11/03)
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- Commercial Pd/C-Catalyzed N-Methylation of Nitroarenes and Amines Using Methanol as Both C1 and H2 Source
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Herein, we report commercially available carbon-supported-palladium (Pd/C)-catalyzed N-methylation of nitroarenes and amines using MeOH as both a C1 and a H2 source. This transformation proceeds with high atom-economy and in an environmentally friendly way via borrowing hydrogen mechanism. A total of >30 structurally diverse N-methylamines, including bioactive compounds, were selectively synthesized with isolated yields of up to 95%. Furthermore, selective N-methylation and deuteration of nimesulide, a nonsteroidal anti-inflammatory drug, were realized through the late-stage functionalization.
- Goyal, Vishakha,Gahtori, Jyoti,Narani, Anand,Gupta, Piyush,Bordoloi, Ankur,Natte, Kishore
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p. 15389 - 15398
(2019/12/04)
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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p. 14627 - 14635
(2019/12/02)
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- Synergistic catalysis of Cu+/Cu0 for efficient and selective N-methylation of nitroarenes with para-formaldehyde
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In this paper, an inexpensive heterogeneous copper nanoparticles catalyst derived from CuAl-layered double hydroxide via an in situ topotactic transformation process was developed. Cu nanoparticles with uniform size were homogeneously dispersed on amorphous Al2O3 with strong metal-support interaction. Characterization results reveals that the Cu0 and Cu+ were simultaneously formed with Cu+ species as the dominant sites on the surface during the reduction process. The resultant catalyst Cu/Al2O3 demonstrates high catalytic activity, selectivity and durability for the reductive N-methylation of easily available nitroarenes in a cost-efficient, environmentally friendly and cascade manner. A broad spectrum of nitroarenes could be efficiently N-methylated to their corresponding N,N-dimethyl amines with good compatibility of various functional groups. The protocol is also applicable for the late-stage functionalization of biologically and pharmaceutically active nitro molecules. A structure-function relationship discloses that Cu0 and Cu+ sites on the surface pronouncedly boosts the reaction efficiency in a synergistic manner, in which Cu0 could facilitate H2 production and N-methylation of anilines, while Cu+ is considerably more active and participates in the overall process of the selective N-methylation of nitroarenes. Moreover, the catalyst also showed a strong stability and could be easily separated for successive reuses without an appreciable loss in activity and selectivity.
- Dong, Xiaosu,Wang, Zhaozhan,Yuan, Youzhu,Yang, Yong
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p. 304 - 313
(2019/07/02)
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- Hydrosilane-Promoted Facile Deprotection of tert-Butyl Groups in Esters, Ethers, Carbonates, and Carbamates
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Combination of PdCl2 with 1,1,3,3-tetramethyldisiloxane in the presence of activated carbon was found to be an effective catalyst system for the cleavage reaction of C?O bond of O?t-Bu moieties. The present catalytic reaction offers a practical method for the deprotection of tert-butyl esters, tert-butyl ethers, O-Boc, and N-Boc derivatives under mild conditions. The addition of activated carbon in the reaction mixture was proved to be crucial for not only sustaining the catalytic activity but also trapping the palladium species after the reaction. (Figure presented.).
- Ikeda, Takuya,Zhang, Zhenzhong,Motoyama, Yukihiro
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supporting information
p. 673 - 677
(2019/01/04)
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- Palladium-Catalyzed Methylation of Nitroarenes with Methanol
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A procedure for the synthesis of N-methyl-arylamines directly from nitroarenes using methanol as green methylating agent was developed. The key to success is the use of a specific catalyst system consisting of palladium acetate and the ligand 1-[2,6-bis(isopropyl)phenyl]-2-[tert-butyl(2-pyridinyl)phosphino]-1H-Imidazole (L1). The generality of this protocol is demonstrated in the synthesis of more than 20 N-methyl-arylamines under comparably mild conditions. Combining this novel methodology with subsequent coupling processes using the same catalyst allows for efficient diversification of aromatic nitro compounds to a broad variety of amines including drug molecules.
- Wang, Lin,Neumann, Helfried,Beller, Matthias
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supporting information
p. 5417 - 5421
(2019/04/04)
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- Iridium-Catalyzed Highly Efficient and Site-Selective Deoxygenation of Alcohols
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An iridium-catalyzed, highly efficient, and site-selective deoxygenation of primary, secondary, and tertiary alcohols has been realized, under the assistance of a 4-(N-substituted amino)aryl directing group. Only the hydroxyl adjacent to the directing group can be deoxygenated. The deoxygenation is performed in water, with formic acid as both the promoter and hydride donor. Excellent yields and functionality tolerance, as well as high efficiency (S/C up to 1000 000, TOF up to 445 000 h-1), are obtained. The kinetic isotope effect studies show that hydride formation is the rate-determining step, and the deoxygenation follows an SN1-type pathway. The deoxygenation protocol has been demonstrated useful in the structural modification of naturally occurring ketones and steroids.
- Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
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p. 9320 - 9326
(2018/09/21)
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