- B(C6F5)3-catalyzed methylation of amines using CO2 as a C1 building block
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B(C6F5)3 was proven to be an efficient metal-free catalyst for the methylation of amines using CO2 as a C1 building block in the presence of hydrosilanes under easy-handling conditions. A broad range of N-alkylanilines, dialkylamines and primary anilines all proceeded well under the catalytic conditions.
- Yang, Zhenzhen,Yu, Bo,Zhang, Hongye,Zhao, Yanfei,Ji, Guipeng,Ma, Zhishuang,Gao, Xiang,Liu, Zhimin
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- Bis- n -heterocyclic carbene (nhc) stabilized η6-arene iron(0) complexes: Synthesis, structure, reactivity, and catalytic activity
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Reaction of FeCl2 with the chelating bis-N-heterocyclic carbene (NHC) bis-(N-Dipp-imidazole-2-ylidene)methylene (abbreviated {( DippC:)2CH2}) (Dipp = 2,6-di-isopropylphenyl) affords the complex [FeCl2{(DippC:)2CH 2}] (1) in high yield. Reduction of complex 1 with excess KC 8 with a 10-fold molar excess of PMe3 affords the Fe(II) complex [FeH{(DippC:)2CH2}(PMe 3)(η2-PMe2CH2)] (2) as a mixture of three stereoisomers. Complex 2, the first example of any iron(II) complex bearing mutually an NHC and PMe3 ligand, is likely obtained from the in situ, reductively generated 16 VE Fe(0) complex, [Fe{(DippC:) 2CH2}(PMe3)2] (2′), following intramolecular C-H activation of one of the phosphorus-bound CH3 groups. Complex 2 is unstable in aromatic solvents and forms, via a novel synthetic transformation involving intramolecular reductive elimination and concomitant PMe3 elimination, the Fe (0) arene complex [Fe{( DippC:)2CH2}(η6-C 6D6)] (4-d6) in C6D6. Complex 4-d6 represents the first example of an NHC stabilized iron (0) arene complex. The transformation from 2 to 4-d6 can be accelerated at higher temperature and at 60 C forms immediately. Alternatively, the reduction of 1 in the presence of toluene or benzene affords the complexes [Fe{(DippC:)2CH2}(η6-C 7H8)] (3) and [Fe{(DippC:)2CH 2}(η6-C6H6)] (4), selectively and in good yields. DFT calculations characterizing the bonding situation in 3 and 4 reveal similar energies of the HOMO and LUMO orbitals, with the LUMO orbital of both complexes located on the Dipp rings of the bis-NHC. The HOMO orbital reflects a π-back-bonding interaction between the Fe(0) center and the chelating NHC ligand, while the HOMO-1 is associated with the arene interaction with the Fe(0) site. The calculations do not suggest any noninnocence of the coordinated arene in either complex. Moreover, the 57Fe Moessbauer spectrum of 4 at 80K exhibits parameters (δ = 0.43 mm·s-1; ΔEQ = 1.37 mm·s -1) which are consistent with a five-coordinate Fe(0) system, rendering 3 and 4 the first examples of well-defined authentic Fe(0)-η6-arene complexes of the type [Fe(η6-arene) L2] (L = η1 or 2 neutral ligand, mono or bidentate). Some reactivitiy studies of 3 are also reported: The reaction of 3 with excess CO selectively yields the five-coordinate piano-stool complex [Fe{( DippC:)2CH2}(CO)3] (6) in near quantitative yields, while the reaction of complex 3 with C6D 6 under heating affords by toluene elimination 4-d6. The catalytic ability of 4 was also investigated with respect to amide reduction to amines, for a variety of substrates using Ph2SiH2 as a hydride source. In all cases good to excellent yields to the corresponding amines were obtained. The use of 4 as a precatalyst represents the first example of a well-defined Fe(0) complex to effect this catalytic process.
- Blom, Burgert,Tan, Gengwen,Enthaler, Stephan,Inoue, Shigeyoshi,Epping, Jan Dirk,Driess, Matthias
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- Metalated Mesoporous Poly(triphenylphosphine) with Azo Functionality: Efficient Catalysts for CO2 Conversion
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Mesoporous poly(triphenylphosphine) with azo functionality (poly(PPh3)-azo) is reported, which was synthesized via oxidative polymerization of P(m-NH2Ph)3 at ambient conditions. This kind of polymer could strongly coordinate with metal ions (e.g., Ru3+) and could reduce Ag+ in situ to metallic form. The resultant metalated poly(PPh3)-azo (e.g., poly(PPh3)-azo-Ag or -Ru) were discovered to be highly efficient catalysts for CO2 transformation. Poly(PPh3)-azo-Ag showed more than 400 times higher site-time-yield (STY) for the carboxylative cyclization of propargylic alcohols with CO2 at room temperature compared with the best heterogeneous catalyst reported. Poly(PPh3)-azo-Ru also exhibited good activity for the methylation of amines with CO2. It was demonstrated that the high performances of the catalysts originated from the cooperative effects between the polymer and the metal species. In addition, both catalysts showed good stability and easy recyclability, thus demonstrating promising potential for practical utilization for the conversion of CO2 into value-added chemicals.
- Yang, Zhenzhen,Yu, Bo,Zhang, Hongye,Zhao, Yanfei,Chen, Yu,Ma, Zhishuang,Ji, Guipeng,Gao, Xiang,Han, Buxing,Liu, Zhimin
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- Photochemical Activation of Tertiary Amines for Applications in Studying Cell Physiology
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Representative tertiary amines were linked to the 8-cyano-7-hydroxyquinolinyl (CyHQ) photoremovable protecting group (PPG) to create photoactivatable forms suitable for use in studying cell physiology. The photoactivation of tamoxifen and 4-hydroxytamoxifen, which can be used to activate Cre recombinase and CRISPR-Cas9 gene editing, demonstrated that highly efficient release of bioactive molecules could be achieved through one- and two-photon excitation (1PE and 2PE). CyHQ-protected anilines underwent a photoaza-Claisen rearrangement instead of releasing amines. Time-resolved spectroscopic studies revealed that photorelease of the tertiary amines was extremely fast, occurring from a singlet excited state of CyHQ on the 70 ps time scale.
- Asad, Naeem,Deodato, Davide,Lan, Xin,Widegren, Magnus B.,Phillips, David Lee,Du, Lili,Dore, Timothy M.
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- Reaction of alkyl sulfoxides and phenylphosphinic acid with amines. Alternative reagents for secondary amines N-alkylation
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Phenylphosphinic acid and dialkylsulfoxides are found to be alternative reagents for respectively the reducing reagent (formic acid) and the alkylating reagent (aldehyde) currently used for secondary amines N-alkylation. Primary amines do not react with this system, but phenylglycine is decarboxilated to benzylamine.
- Chauvin
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- Borinic Acid Catalysed Reduction of Tertiary Amides with Hydrosilanes: A Mild and Chemoselective Synthesis of Amines
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A reduction of various aryl, alkyl, and α,β-unsaturated amides with phenylsilane, catalysed by a borinic acid, is reported. The unprecedented reaction was carried out under very mild conditions and led to useful amines. Furthermore, the reaction tolerates a variety of functional groups. Initial investigations implicated that an intermediate diarylhydroborane is involved in the reaction mechanism.
- Chardon, Aurélien,Mohy El Dine, Tharwat,Legay, Rémi,De Paolis, Micha?l,Rouden, Jacques,Blanchet, Jér?me
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- Chemoselective Reduction of Tertiary Amides to Amines Catalyzed by Triphenylborane
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Triphenylborane (BPh3) was found to catalyze the reduction of tertiary amides with hydrosilanes to give amines under mild condition with high chemoselectivity in the presence of ketones, esters, and imines. N,N-Dimethylacrylamide was reduced to provide the α-silyl amide. Preliminary studies indicate that the hydrosilylation catalyzed by BPh3may be mechanistically different from that catalyzed by the more electrophilic B(C6F5)3.
- Mukherjee, Debabrata,Shirase, Satoru,Mashima, Kazushi,Okuda, Jun
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- Base-promoted elimination reactions of acetaldehyde N-alkyl-N,N-dimethylhydrazonium salts. A convenient synthesis of N,N-dimethylalkylamines
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The title reaction was utilized for efficient conversion of S(N)2-reactive alkyl halides to the corresponding N,N-dimethylalkylamines.
- Smith,Marcucci,Tingue
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- Efficient and Selective N-Methylation of Nitroarenes under Mild Reaction Conditions
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Herein, we report a straightforward protocol for the preparation of N,N-dimethylated amines from readily available nitro starting materials using formic acid as a renewable C1 source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane-type Mo3PtS4 catalyst. For the preparation of the novel [Mo3Pt(PPh3)S4Cl3(dmen)3]+ (3+) (dmen: N,N′-dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo3S4Cl3(dmen)3]+ (1+) and Pt(PPh3)4 (2) complexes. The heterobimetallic 3+ cation preserves the main structural features of its 1+ cluster precursor. Interestingly, this catalytic protocol operates at room temperature with high chemoselectivity when the 3+ catalyst co-exists with its trinuclear 1+ precursor. N-heterocyclic arenes, double bonds, ketones, cyanides and ester functional groups are well retained after N-methylation of the corresponding functionalized nitroarenes. In addition, benzylic-type as well as aliphatic nitro compounds can also be methylated following this protocol.
- Pedrajas, Elena,Sorribes, Iván,Guillamón, Eva,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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- Base-Catalyzed Hydrosilylation of Nitriles to Amines and Esters to Alcohols
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Base-catalyzed hydrosilylation of nitriles to amines and esters to silylated alcohols is reported. This protocol tolerates electron-rich and electron-neutral olefins and works in the presence of basic functional groups (e. g. tertiary amines) but fails for acidic substrates, such as phenols and NH anilines. This catalytic system does not tolerate carbonyl groups, such as aldehydes, ketones, esters and carbamides, which are reduced to corresponding alcohols and amines. With the exact amount of silane, esters can be selectively reduced in the presence of nitriles, but the selectivity drops for the pairs ester/carboxamide and carboxamide/nitrile. Through competition experiments, the following preference in functional group reactivity was determined: ester > carboxamide > nitrile.
- Clarke, Joshua A.,Nikonov, Georgii I.,van der Est, Art
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- Azo-functionalized microporous organic polymers: Synthesis and applications in CO2 capture and conversion
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Azo-functionalized MOPs (Azo-MOPs) were synthesized via oxidative polymerization of aromatic amines catalyzed by t-BuOCl/NaI (25 °C, 1 h, yield: >95%), which displayed an excellent coordinating ability with a Ru complex. The resulting Ru-coordinated Azo-MOPs displayed high CO2 capacity and high performances for catalyzing the methylation of amines with CO2 under low pressure (0.5 MPa).
- Yang, Zhenzhen,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Ma, Zhishuang,Ji, Guipeng,Han, Buxing,Liu, Zhimin
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- Lithium compound catalyzed deoxygenative hydroboration of primary, secondary and tertiary amides
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A selective and efficient route for the deoxygenative reduction of primary to tertiary amides to corresponding amines has been achieved with pinacolborane (HBpin) using simple and readily accessible 2,6-di-tert-butyl phenolate lithium·THF (1a) as a catalyst. Both experimental and DFT studies provide mechanistic insight. This journal is
- Bisai, Milan Kumar,Gour, Kritika,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
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- Synthesis of N,N-dimethylamines via Barbier-Grignard-type electrophilic amination
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Aryl Grignard reagents react with N,N-dimethyl O-(mesitylenesulfonyl)- hydroxylamine in THF under Barbier conditions at room temperature and give N,Ndimethylanilines with high yields in a 2-h reaction. The amination yield of in situ Grignard reagents were not lower than those of preformed aryl Grignard reagents. In situ cycloalkyl-, allyl-, and benzylmagnesium bromides did not react with N,Ndimethyl O-(mesitylenesulfonyl)hydroxylamine, except that amination of in situ n-hexylmagnesium bromide resulted in a medium yield. Grignard-Barbier-type amination of aryl bromides with N,N-dimethyl O-(mesitylenesulfonyl)hydroxylamine provides a new alternative route for the synthesis of N,N-dimethylanilines. Copyright Taylor & Francis Group, LLC.
- Erdik, Ender,Ates, Selma
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- Self-encapsulation of homogeneous catalyst species into polymer gel leading to a facile and efficient separation system of amine products in the Ru-catalyzed reduction of carboxamides with polymethylhydrosiloxane (PMHS)
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A practical procedure for production of amines is offered by the ruthenium-catalyzed reduction of carboxamides with polymethylhydrosiloxane, in which encapsulation of the catalyst species into the formed insoluble siloxane resins contributes to the separation of both metallic and siloxane residues from the product. Copyright
- Motoyama, Yukihiro,Mitsui, Kaoru,Ishida, Toshiki,Nagashima, Hideo
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- Fast N-methylation of amines under microwave irradiation
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Primary and secondary amines are quickly N-methylated by methanal and formic acid under microwave irradiation.
- Barbry, Didier,Torchy, Severine
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- Transformation of Monoamine Oxidase-B Primary Amine Substrates into Time-Dependent Inhibitors. Tertiary Amine Homologues of Primary AMine Substrates
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A family of N-methylated and N,N-dimethylated alkyl and arylalkylamines was prepared and more than half of the analogues were shown to be time-dependent pseudo-first-order inhibitors of monoamine oxidase-B.Some of the time-dependent inactivators were reversible and others were irreversible with respect to prolonged dialysis following inactivation.Partition ratios ranged from zero to 11 000.These results are rationalized in terms of a combination of an inductive effect and a stereoelectronic effect as a result of hindered rotation of an active site covalent adduct.A molecualr mechanics calculation indicates that there is at least 10 kcal/mol of torsional energy to be overcome in order for the enzyme adduct to be released.These findings show that tertiary amine homologues of primary amine substrates of monoamino oxidase are time-dependent inhibitors, and this should be useful in the design of new inactivators of this enzyme.
- Ding, Charles Z.,Lu, Xingliang,Nishimura, Kuniko,Silverman, Richard B.
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- Studies into reactions of N-methylmorpholine-N-oxide (NMMO) and its hydrates with cyanuric chloride
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The course of the reaction between N-methylmorpholine-N-oxide (NMMO, 1a) and cyanuric chloride (2) is strictly dependent on the hydrate water content of the amine oxide. In solid phase, both substances undergo an explosion-like, extremely exothermic reaction. In solution, this process becomes controllable and leads to a quantitative degradation of NMMO into morpholine and formaldehyde, with 2 only acting as an inducing agent. The reaction can be conducted in a way that a clean deoxygenative demethylation is achieved. The monohydrate of NMMO (1b) is quantitatively converted into N-methylmorpholine and hypochlorous acid by the action of 2. This conversion can be used in synthesis either to deoxygenate tertiary amine N-oxide monohydrates, or to produce chlorohydrins in non-aqueous, organic media in superior yields. The semisesquihydrate of NMMO (1c) reacts with 2 under consumption of water until non-hydrated NMMO is present, which is then further converted into morpholine and HCHO, as in the case of 1a being directly employed as the starting material.
- Rosenau, Thomas,Potthast, Antje,Kosma, Paul
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- Transition metal-free methylation of amines with formaldehyde as the reductant and methyl source
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A simple transition metal-free procedure using formaldehyde for the N,N-dimethylation and N-methylation of primary and secondary anilines is reported. The reaction showed limitations on sterically hindered and electron-withdrawing anilines, but is successful on amines with electron-donating substituents. Formaldehyde acts as both the reducing agent and the carbon source in the reaction.
- Man, Nikki Y.T.,Li, Wanfang,Stewart, Scott G.,Wu, Xiao-Feng
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- Iminopinacol coupling with lithium: Electron-transfer mediators
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The addition of tert-butyl borate or ethyl formate to N-alkylbenzalimines directs the reaction pathway from the Birch reduction to the pinacol-type coupling with lithium in THF; an analogous reaction with a dimethylimmonium salt requires a trace titanium catalyst as the electron-transfer mediator.
- Mistryukov, Electron A.
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- Thermal Decomposition of Dimethylnitramine and Dimethylnitrosamine by Pulsed Laser Pyrolysis
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Pyrolysis of dimethylnitramine (DMNA) and dimethylnitrosamine (DMNO) was carried out in a flow system over the temperature range 800-900 K using pulsed infrared laser heating, via SF6 in a 250-Torr bath of CO2 and radical scavanger.Arrhenius parameters for DMNO and DMNA composition were log k(s-1)=(15.8+/-1.1)-(50.0+/-3.4)/2.3RT and (13.5+/-0.6)-(37.4+/-2.5)/2.3RT, respectively.The former set of parameters is consistentwith simple bond scission as the rate-limiting step; the latter set, which was produced with different scavengers, temperature standards, and varying amounts of added NO as a radical trap, is not consistent with simple bond scission.The experimental reaults can be reproduced via a mechanistic numerical model in which N-NO2 bond scission and nitro-nitrite rearrangement are competitive initial steps and the displacement of NO2 from DMNA by NO is included as a low-temperature route to DMNO.
- Nigenda, S. Esther,McMillen, Donald F.,Golden, David M.
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- Simple Amine-Directed Meta-Selective C-H Arylation via Pd/Norbornene Catalysis
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Herein we report a highly meta-selective C-H arylation using simple tertiary amines as the directing group. This method takes advantage of Pd/norbornene catalysis, offering a distinct strategy to control the site selectivity. The reaction was promoted by commercially available AsPh3 as the ligand and a unique "acetate cocktail". Aryl iodides with an ortho electron-withdrawing group were employed as the coupling partner. A wide range of functional groups, including some heteroarenes, are tolerated under the reaction conditions. In addition, the amine directing group can be easily installed and transformed to other common versatile functional groups. We expect this C-H functionalization mode to have broad implications for developing other meta-selective transformations beyond this work.
- Dong, Zhe,Wang, Jianchun,Dong, Guangbin
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- Sustainable heterogeneous platinum catalyst for direct methylation of secondary amines by carbon dioxide and hydrogen
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Pt and MoOx co-loaded TiO2 is found to be highly effective for direct methylation of aliphatic and aromatic secondary amines by CO2 and H2 under solvent-free conditions. This is the first additive-free and reusable heterogeneous catalytic system with acceptable turnover number. Over and over: A heterogeneous Pt catalyst for direct methylation of aromatic amines by CO2 and H2 with high reusability and an order of magnitude higher turnover number than previous catalysts has been demonstrated (see scheme).
- Kon, Kenichi,Siddiki, S. M. A. Hakim,Onodera, Wataru,Shimizu, Ken-Ichi
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- N,N-Diethylaniline·borane, an efficient reducing agent for reduction of representative functional groups
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N,N-Diethylaniline·borane (DEANB), a thermally stable, commercially available, amine·borane reagent, reduces a variety of functional groups, such as aldehydes, ketones, carboxylic acids, tertiary amides, and lactams in excellent yields. It also reduces Schiff bases to the corresponding amines in very good yields. Besides these reducing properties, it readily hydroborates 1-octene to provide the trialkylborane which in turn on alkaline peroxide oxidation furnished the 1-octanol in excellent yield and usual regioselectivity.
- Salunkhe, Ashok M.,Burkhardt, Elizabeth R.
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- Experimental and computational studies of borohydride catalyzed hydrosilylation of a variety of C=O and C=N functionalities including esters, amides and heteroarenes
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Sodium borohydride and a series of related borohydrides catalyze a transition metal-free hydrosilylation of a variety of C=O and C=N functionalities under mild conditions. Importantly, many of these reactions are possible using the cheap and environmentally benign hydrosilane polymethylhydrosiloxane. A mechanism is proposed based on experimental and computational results.
- Manas, Michael G.,Sharninghausen, Liam S.,Balcells, David,Crabtree, Robert H.
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- Mild and Efficient Flavin-Catalyzed H2O2 Oxidation of Tertiar Amines to Amine N-Oxides
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A mild and highly effective H2O2 oxidation of tertiary amines has been developed by the use of flavin catalysis. Eight aliphatic amines were oxidized to their corresponding N-oxides in fast and selective reactions. For all substrates a considerable rate enhancement was observed compared to the noncatalyzed reactions. The product N-oxides were isolated in good yields using this mild oxidation system based on the environmentally attractive oxidant H2O2. As the catalyst, an N1N5- dialkylated flavin was used as an analogue of the biologically important flavin redox cofactor. The catalytic cycle proposed for the flavin catalysis accounts for the observation that, in addition to the hydrogen peroxide oxidant, molecular oxygen is required for the initiation of the process.
- Bergstad, Katarina,B?ckvall, Jan-E.
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- Formation of octahedral iridium(III) dihydrides from the reaction of ortho-chelated aryliridium(I) compounds with dihydrogen
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The reaction of IrI[C6H2(CH2NMe 2)-2-R1-4-R2-6](COD) (COD = cycloocta-1,5-diene) with dihydrogen in CD2Cl2 was monitored by 1H NMR. At -20°C quan
- Van Der Zeijden, Adolphus A. H.,Van Koten, Gerard,Luijk, Ronald,Grove, David M.
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- Reductive methylation using decaborane in methanol
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Amines (primary and secondary) were methylated to the corresponding tertiary amine using 37% formaldehyde and decaborane in methanol at room temperature under nitrogen in high yields.
- Yeon Joo Jung,Jong Woo Bae,Choon-Ock Maing Yoon,Byung Woo Yoo,Cheol Min Yoon
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- A novel strategy for oligopeptide synthesis using a polymer-supported ammonium fluoride
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A novel method for the preparation of oligopeptides with a PS-ammonium fluoride in the solution phase is reported. The synthesis of lipid II pentapeptide is efficiently synthesized via a PS-ammonium fluoride without chromatographic purifications. The method reported here is very convenient to synthesize a relatively large amount of oligopeptides with abundantly available Fmoc-protected amino acids in a time efficient manner.
- Kurosu, Michio,Crick, Dean C.
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- Dual antitumor and antiangiogenic activity of organoplatinum(II) complexes
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A library of over 20 cycloplatinated compounds of the type [Pt(dmba-R)LCl] (dmba-R = C,N-dimethylbenzylamine-like ligand; R being MeO, Me, H, Br, F, CF3, and NO2 substituents in the R5 or R4 position of the phenyl ring; L = DMSO and P(C6H4CF3-p)3) has been prepared. All compounds are active in both human ovarian carcinoma A2780 cells and cisplatin-resistant A2780cisR cells, with most of the DMSO platinum complexes exhibiting IC50 values in the submicromolar range in the A2780 cell line. Interestingly, DMSO platinum complexes show low cytotoxicity in the nontumorigenic kidney cell line BGM and therefore high selectivity factors SF. In addition, some of the DMSO platinum complexes effectively inhibit angiogenesis in the human umbilical vein endothelial cell line EA.hy926. These are the first platinum(II) complexes reported to inhibit angiogenesis at a close concentration to their IC50 in A2780 cells, turning them into dual cytotoxic and antiangiogenic compounds.
- Zamora, Ana,Pérez, Sergio A.,Rodríguez, Venancio,Janiak, Christoph,Yellol, Gorakh S.,Ruiz, José
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- MANNICH REACTIONS OF ARYL-TRIALKYLSTANNANES USING PREFORMED DIALKYL-METHYLENEIMINIUM SALTS
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Dialkyl-methyleneiminium salts react with aryl-tributyl- and aryl-trimethylstannanes to afford the corresponding N,N-dialkylaminomethyl- derivatives in good yields.The method can be used to obtain isomers that are not obtained by classical procedures.
- Cooper, Mark S.,Heaney Harry
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- Additive-free selective methylation of secondary amines with formic acid over a Pd/In2O3 catalyst
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Formic acid is used as the sole carbon and hydrogen source in the methylation of aromatic and aliphatic amines to methylamines. The reaction proceeds via a formylation/transfer hydrogenation pathway over a solid Pd/In2O3 catalyst without the need for any additive.
- Benaissa, Idir,Cantat, Thibault,Genre, Caroline,Godou, Timothé,Pinault, Mathieu
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- Reductive Alkylation of Azides and Nitroarenes with Alcohols: A Selective Route to Mono- And Dialkylated Amines
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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.
- Borthakur, Ishani,Joshi, Abhisek,Kundu, Sabuj,Maji, Milan
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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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- Simplified preparation of a graphene-co-shelled Ni/NiO@C nano-catalyst and its application in theN-dimethylation synthesis of amines under mild conditions
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The development of Earth-abundant, reusable and non-toxic heterogeneous catalysts to be applied in the pharmaceutical industry for bio-active relevant compound synthesis remains an important goal of general chemical research.N-methylated compounds, as one of the most essential bioactive compounds, have been widely used in the fine and bulk chemical industries for the production of high-value chemicals. Herein, an environmentally friendly and simplified method for the preparation of graphene encapsulated Ni/NiO nanoalloy catalysts (Ni/NiO@C) was developed for the first time, for the highly selective synthesis ofN-methylated compounds using various functional amines and aldehydes under easy to handle, and industrially applicable conditions. A large number of primary and secondary amines (more than 70 examples) could be converted to the correspondingN,N-dimethylamines with the participation of different functional aldehydes, with an average yield of over 95%. A gram-scale synthesis also demonstrated a similar yield when compared with the benchmark test. In addition, it was further proved that the catalyst could easily be recycled because of its intrinsic magnetism and reused up to 10 times without losing its activity and selectivity. Also, for the first time, the tandem synthesis ofN,N-dimethylamine products in a one-pot process, using only a single earth-abundant metal catalyst, whose activity and selectivity were more than 99% and 94%, respectively, for all tested substrates, was developed. Overall, the advantages of this newly developed method include operational simplicity, high stability, easy recyclability, cost-effectiveness of the catalyst, and good functional group compatibility for the synthesis ofN-methylation products as well as the industrially applicable tandem synthesis process.
- Liu, Jianguo,Ma, Longlong,Song, Yanpei,Zhang, Mingyue,Zhuang, Xiuzheng
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supporting information
p. 4604 - 4617
(2021/06/30)
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- Dimethylamination of Primary Alcohols Using a Homogeneous Iridium Catalyst: A Synthetic Method for N, N-Dimethylamine Derivatives
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A new catalytic system for N,N-dimethylamination of primary alcohols using aqueous dimethylamine in the absence of additional organic solvents has been developed. The reaction proceeds via borrowing hydrogen processes, which are atom-efficient and environmentally benign. An iridium catalyst bearing an N-heterocyclic carbene (NHC) ligand exhibited high performance, without showing any deactivation under aqueous conditions. In addition, valuable N,N-dimethylamine derivatives, including biologically active and pharmaceutical molecules, were synthesized. The practical application of this methodology was demonstrated by a gram-scale reaction.
- Jeong, Jaeyoung,Fujita, Ken-Ichi
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p. 4053 - 4060
(2021/03/09)
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- Palladium-Catalyzed Reductive Aminocarbonylation of Benzylammonium Triflates with o-Nitrobenzaldehydes for the Synthesis of 3-Arylquinolin-2(1 H)-ones
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A palladium-catalyzed straightforward procedure for the synthesis of 3-arylquinolin-2(1H)-ones has been developed. The synthesis proceeds through a palladium-catalyzed reductive aminocarbonylation reaction of benzylic ammonium triflates with o-nitrobenzaldehydes, and a wide range of 3-arylquinolin-2(1H)-ones was obtained in moderate to good yields with very good functional group compatibility.
- Liu, Yongzhu,Qi, Xinxin,Wu, Xiao-Feng
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p. 13824 - 13832
(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 0048-0056; 0058
(2021/03/13)
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- Method for preparing amine compound by reducing amide compound
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The invention relates to a method for preparing an amine compound by reducing an amide compound, which comprises the following steps: in a protective atmosphere, mixing the amide compound or cyclic amide, a zirconium metal catalyst and pinacol borane, carrying out amide reduction reaction at room temperature, and carrying out aftertreatment by using an ether solution of hydrogen chloride after 12-48 hours to obtain an amine hydrochloride compound. The method is simple to operate, low in cost, good in functional group tolerance and wide in substrate range.
- -
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Paragraph 0031-0057
(2021/02/10)
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- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
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Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
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p. 2059 - 2067
(2021/09/02)
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
-
supporting information
p. 9204 - 9207
(2021/09/20)
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- Manganese-Catalyzed Hydroborations with Broad Scope
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Reductive transformations of easily available oxidized matter are at the heart of synthetic manipulation and chemical valorization. The applications of catalytic hydrofunctionalization benefit from the use of liquid reducing agents and operationally facile setups. Metal-catalyzed hydroborations provide a highly prolific platform for reductive valorizations of stable C=X electrophiles. Here, we report an especially facile, broad-scope reduction of various functions including carbonyls, carboxylates, pyridines, carbodiimides, and carbonates under very mild conditions with the inexpensive pre-catalyst Mn(hmds)2. The reaction could be successfully applied to depolymerizations.
- Ghosh, Pradip,Jacobi von Wangelin, Axel
-
supporting information
p. 16035 - 16043
(2021/06/16)
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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
-
supporting information
p. 13122 - 13135
(2021/08/31)
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- Method for preparing tertiary amine organic compound from photocatalytically decomposing substituted formamide
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The invention discloses a method for preparing a tertiary amine compound from aldehyde and substituted formamide under the action of a photocatalyst. The method is characterized in that the reaction can be performed only by illumination under the conditions of no hydrogen and no reducing agent. The method is suitable for various aldehydes including aromatic aldehydes, fatty aldehydes and the like,has the characteristics of few byproducts and high product yield, does not need to use hydrogen in the reaction, avoids the use of noble metal hydrogenation catalysts, and has obvious technical and economic effects and application prospects.
- -
-
Paragraph 0026-0028
(2021/01/12)
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- Method for preparing tertiary amine organic compound by decomposing substituted formamide under mild condition
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The invention discloses a method for preparing tertiary amine organic compounds by decomposing substituted formamide under mild conditions, which comprises the following steps: heating and stirring aldehydes serving as a reaction substrate, substituted formamide serving as a solvent, a reducing agent and an amination reagent, Ti-based oxide/hydroxide serving as a catalyst and a small amount of water serving as an auxiliary agent to generate the corresponding tertiary amine compound. Hydrogen is not needed in the reaction process. The method can be suitable for various aldehydes including aromatic aldehydes, fatty aldehydes and the like, and has the characteristics of high conversion rate and single product, and the tertiary amine compound can be simply, efficiently and safely synthesized without using hydrogen and noble metals in the reaction, so that the method has remarkable economic effects and application prospects.
- -
-
Paragraph 0025-0027; 0049
(2021/06/13)
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- BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
-
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.
- Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
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supporting information
p. 5205 - 5211
(2021/07/29)
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- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
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Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
-
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- Bis-(triphenylphosphane) Aluminum Hydride: A Simple Way to Provide, Store, and Use Non-Polymerized Alane for Synthesis
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AlH3(PPh3)2 was synthesized as a stable solid being the first known 1 : 2 alane arylphosphane adduct. Although only weakly intra-molecularly coordinated, it displays as a molecular crystal significant inertness against atmospheric humidity and oxygen due to strong steric screening of the alane unit. The compound readily dissociates PPh3 in solution allowing for its use as a Lewis acidic reducing agent. These features lead to an easy to store, easy to use reducing agent that may enable the quantitative investigation of aluminum hydride chemistry including reduction, complexation and hydroalumination reactions. The structure contains two non-equivalent penta-coordinated aluminum centers that despite long Al?P distances of ca. 2.7 ? display unusually high quadrupolar coupling constants CQ of 25.1 and 26.5 in 27Al solid state NMR measurements. The product was also tested as a reducing agent on a small set of selected compounds with various functional groups.
- Anders, Martin,Brendler, Erica,Kaiser, Stefan,Mertens, Florian,Pollex, Rolf,Sandig-Predzymirska, Lesia,Schumann, Erik,Schwarzer, Anke
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p. 1193 - 1198
(2021/08/31)
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- Heterogeneous Catalyzed Chemoselective Reductive Amination of Halogenated Aromatic Aldehydes
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The chemoselective conversion of a specific functional group in a multifunctional substrate is of great importance in the chemical industry to obtain cost efficient, sustainable and waste free processes. This work focuses on the chemoselective amination of halogenated aromatic aldehydes with dimethyl amine towards halogenated aromatic amines, a raw material used in the production of for example agrochemical active ingredients. It was found that by combining palladium, a metal known for dehalogenation reactions, and copper, known for its direct hydrogenation of aldehydes to alcohols, in one heterogeneous bimetallic catalyst, a synergistic effect is obtained. By depositing copper onto a palladium on carbon catalyst with a Cu/Pd ratio of at least 1 : 1, the yield could be increased from 66 % (Pd/C) to 98 % (PdCu/C). Moreover, this highly active and stable catalyst also showed suppressed dehalogenation side-reactions in several other chemical conversions such as hydrogenation of nitro functional groups and hydrogenation of aldehydes.
- Dumoleijn, Kim N. R.,Villa, Alberto,Marelli, Marcello,Prati, Laura,Moonen, Kristof,Stevens, Christian V.
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p. 3021 - 3026
(2021/05/18)
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- Preparation method of N-alkylated derivative of primary amine compound
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The invention relates to a preparation method of an N-alkylated derivative of a primary amine compound. The method comprises the following steps: uniformly mixing a primary amine compound, an alcohol compound and a catalyst in a reactor, and heating to react for a period of time to generate an N-alkylated substituted tertiary amine compound; wherein the catalyst is a copper-cobalt bimetallic catalyst, and the carrier of the catalyst is Al2O3. According to the method, alcohol is adopted as an alkylating reagent and is low in price and easy to obtain, a byproduct is water, no pollution is caused to the environment, and the overall reaction atom economy is high; the catalyst is simple in preparation method, low in cost, high in reaction activity and good in structural stability; meanwhile, by using the copper-cobalt bimetallic catalyst, the use of strong base additives can be avoided, and the requirement on reaction equipment is low; and the reaction post-treatment is convenient, and the catalyst can be recycled and is environment-friendly.
- -
-
Paragraph 0021; 0050
(2021/07/09)
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- Catalyst-free selective: N -formylation and N -methylation of amines using CO2 as a sustainable C1 source
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We herein describe catalyst-free selective N-formylation and N-methylation of amines using CO2 as a sustainable C1 source. By tuning the reaction solvent and temperature, the selective synthesis of formamides and methylamines is achieved in good to excellent yields using sodium borohydride (NaBH4) as a sustainable reductant.
- Zou, Qizhuang,Long, Guangcai,Zhao, Tianxiang,Hu, Xingbang
-
supporting information
p. 1134 - 1138
(2020/03/11)
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- Silicon hydrogenation reaction method of organic boron and inorganic alkali catalysis amide (by machine translation)
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The method is characterized in that organic boron and inorganic bases are used as catalysts, silane is used as a reducing agent, primary amide is reduced to primary amine or dehydration dinitrile, the secondary amide is reduced to a secondary amine or aldimine, and the tertiary amide is reduced to tertiary amine. The method has the advantages of simple operation, mild reaction conditions, wide substrate universality, good functional group compatibility and the like, and has the characteristics of good stability, cheap and accessible catalyst, simple and convenient operation, high practicality and the like. (by machine translation)
- -
-
Paragraph 0049-0055
(2020/08/18)
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- Erratum: Redox-Noninnocent Ligand-Supported Vanadium Catalysts for the Chemoselective Reduction of C=X (X = O, N) Functionalities (Journal of the American Chemical Society (2019) 141:38 (15230-15239) DOI: 10.1021/jacs.9b07062)
-
Pages 15232, 15233, and 15236. In the original paper, the doublet wave functions for 21 and 21a/21b were incorrectly (Figure Presented). reported as spin-contaminated in sections 2.3 and 2.8 (Figure 3 and Scheme 9, respectively.) This comes from the incorrectly reported expected eigenvalue of 0.75 for the spin-squared operator ??2? for the antiferromagnetically coupled doublet |↓?L|↑↑?V state (originally given in the Supporting Information). The correct expected eigenvalue for the |↓?L|↑↑?V state should be 1.75. The wave functions for 21 and 21a/21b (eigenvalues 1.79 and 1.77/1.66, respectively) are therefore not spincontaminated. The corrected Figure 3 and Scheme 9 are presented below. A corrected Supporting Information file is also provided. The corrections do not affect any of the conclusions of the Article, but slightly decrease the gap between the quartet and doublet spin surfaces. Scheme 3 has been also corrected to reflect the fact that (CH3)3SiCH2 ? radicals can only react based on spin conservation.
- Zhang, Guoqi,Wu, Jing,Zheng, Shengping,Neary, Michelle C.,Mao, Jincheng,Flores, Marco,Trovitch, Ryan J.,Dub, Pavel A.
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supporting information
p. 16507 - 16509
(2020/10/14)
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- Mechanistic Studies on the Insertion of Carbonyl Substrates into Cu-H: Different Rate-Limiting Steps as a Function of Electrophilicity
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We report mechanistic studies on the insertion reactions of [(NHC)Cu(μ-H)]2 complexes with carbonyl substrates by UV-vis and 1H NMR spectroscopic kinetic studies, H/D isotopic labelling, and X-ray crystallography. The results of these comprehensive studies show that the insertion of Cu-H with an aldehyde, ketone, activated ester/amide, and unactivated amide consist of two different rate limiting steps: the formation of Cu-H monomer from Cu-H dimer for more electrophilic substrates, and hydride transfer from a transient Cu-H monomer for less electrophilic substrates. We also report spectroscopic and crystallographic characterization of rare Cu-hemiacetalate and Cu-hemiaminalate moieties from the insertion of an ester or amide into the Cu?H bond.
- Bullock, R. Morris,Gunasekara, Thilina,Neisen, Benjamin D.,Speelman, Amy L.,Tran, Ba L.,Wiedner, Eric S.
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supporting information
p. 8645 - 8653
(2020/04/10)
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- Diethylsilane as a Powerful Reagent in Au Nanoparticle-Catalyzed Reductive Transformations
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Diethylsilane (Et2SiH2), a simple and readily available dihydrosilane, that exhibits superior reactivity, as compared to monohydrosilanes, in a series of reductive transformations catalyzed by recyclable and reusable Au nanoparticles (1 mol-%) supported on TiO2. It reduces aldehydes or ketones almost instantaneously at ambient conditions. It can be used in a one pot rapid reductive amination procedure, in which premixing of aldehyde and amine is required prior to the addition of the reducing agent and the catalyst, even in a protic solvent. An unprecedented method for the synthesis of N-arylisoindolines is also shown in the reductive amination between o-phthalaldehyde and anilines. In this transformation, it is proposed that the intermediate N,2-diphenylisoindolin-1-imines are reduced stepwise to the isoindolines. Finally, Et2SiH2 readily reduces amides into amines in excellent yields and shorter reaction times relative to previously known analogous nano Au(0)-catalyzed protocols.
- Louka, Anastasia,Kidonakis, Marios,Saridakis, Iakovos,Zantioti-Chatzouda, Elisavet-Maria,Stratakis, Manolis
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p. 3508 - 3514
(2020/06/02)
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- Combined KOH/BEt3Catalyst for Selective Deaminative Hydroboration of Aromatic Carboxamides for Construction of Luminophores
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The selective catalytic C-N bond cleavage of amides into value-added amine products is a desirable but challenging transformation. Molecules containing iminodibenzyl motifs are prevalent in pharmaceutical molecules and functional materials. Here we established a combined KOH/BEt3 catalyst for deaminative hydroboration of acyl-iminodibenzyl derivatives, including nonheterocyclic carboxamides, to the corresponding amines. This novel transition-metal-free methodology was also applied to the construction of Clomipramine and luminophores.
- Li, Jinshan,Wang, Jiali,Yang, Jianguo,Yao, Wubing,Zhong, Aiguo
-
supporting information
p. 8086 - 8090
(2020/11/03)
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- Mild catalytic deoxygenation of amides promoted by thorium metallocene
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The organoactinide-catalyzed (Cp*2ThMe2) hydroborated reduction of a wide range of tertiary, secondary, and primary amides to the corresponding amines/amine-borane adductsviadeoxygenation of the amides is reported herein. The catalytic reactions proceed under mild conditions with low catalyst loading and pinacolborane (HBpin) concentration in a selective fashion. Cp*2ThMe2is capable of efficiently catalysing the gram-scale reaction without a drop in efficiency. The amine-borane adducts are successfully converted into free amine products in high conversions, which increases the usefulness of this catalytic system. A plausible mechanism is proposed based on detailed kinetics, stoichiometric, and deuterium labeling studies.
- Eisen, Moris S.,Saha, Sayantani
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p. 12835 - 12841
(2020/10/05)
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- Synthesis of tertiary amines by direct Br?nsted acid catalyzed reductive amination
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Tertiary amines are ubiquitous and valuable compounds in synthetic chemistry, with a wide range of applications in organocatalysis, organometallic complexes, biological processes and pharmaceutical chemistry. One of the most frequently used pathways to synthesize tertiary amines is the reductive amination reaction of carbonyl compounds. Despite developments of numerous new reductive amination methods in the past few decades, this reaction generally requires non-atom-economic processes with harsh conditions and toxic transition-metal catalysts. Herein, we report simple yet practical protocols using triflic acid as a catalyst to efficiently promote the direct reductive amination reactions of carbonyl compounds on a broad range of substrates. Applications of this new method to generate valuable heterocyclic frameworks and polyamines are also included.
- Hussein, Mohanad A.,Dinh, An H.,Huynh, Vien T.,Nguyen, Thanh Vinh
-
supporting information
p. 8691 - 8694
(2020/08/21)
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- Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines
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We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kalevaru, Narayana V.,Kamer, Paul C. J.,Senthamarai, Thirusangumurugan,Zbo?il, Radek
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p. 2973 - 2981
(2020/03/27)
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- Facile synthesis of controllable graphene-co-shelled reusable Ni/NiO nanoparticles and their application in the synthesis of amines under mild conditions
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The primary objective of many researchers in chemical synthesis is the development of recyclable and easily accessible catalysts. These catalysts should preferably be made from Earth-abundant metals and have the ability to be utilised in the synthesis of pharmaceutically important compounds. Amines are classified as privileged compounds, and are used extensively in the fine and bulk chemical industries, as well as in pharmaceutical and materials research. In many laboratories and in industry, transition metal catalysed reductive amination of carbonyl compounds is performed using predominantly ammonia and H2. However, these reactions usually require precious metal-based catalysts or RANEY nickel, and require harsh reaction conditions and yield low selectivity for the desired products. Herein, we describe a simple and environmentally friendly method for the preparation of thin graphene spheres that encapsulate uniform Ni/NiO nanoalloy catalysts (Ni/NiO?C) using nickel citrate as the precursor. The resulting catalysts are stable and reusable and were successfully used for the synthesis of primary, secondary, tertiary, and N-methylamines (more than 62 examples). The reaction couples easily accessible carbonyl compounds (aldehydes and ketones) with ammonia, amines, and H2 under very mild industrially viable and scalable conditions (80 °C and 1 MPa H2 pressure, 4 h), offering cost-effective access to numerous functionalized, structurally diverse linear and branched benzylic, heterocyclic, and aliphatic amines including drugs and steroid derivatives. We have also demonstrated the scale-up of the heterogeneous amination protocol to gram-scale synthesis. Furthermore, the catalyst can be immobilized on a magnetic stirring bar and be conveniently recycled up to five times without any significant loss of catalytic activity and selectivity for the product.
- Cui, Zhibing,Liu, Jianguo,Liu, Qiying,Ma, Longlong,Singh, Thishana,Wang, Chenguang,Wang, Nan,Zhu, Yuting
-
supporting information
p. 7387 - 7397
(2020/11/19)
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- A novel chiral surfactant-type metallomicellar catalyst for asymmetric Michael addition in water
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A series of Schiff-based ligands consisting of both tertiary amines and lipophilic groups were designed and synthesized. Using these ligands, a new chiral surfactant-type metallomicellar catalyst was developed in water, and this was identified by SEM/TEM analyses. These metallomicelles can be empolyed in asymmetric Michael addition reactions in water, delivering the corresponding adducts with excellent yields and enantioselectivities.
- Liang, Xinping,Gui, Yang,Li, Kuiliang,Li, Jindong,Zha, Zhenggen,Shi, Lei,Wang, Zhiyong
-
supporting information
p. 11118 - 11121
(2020/10/05)
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- Synthesis of: N -methylated amines from acyl azides using methanol
-
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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- A Novel Route to Synthesize N,N-Dimethyl Arylmethylamines from Aryl Aldehydes, Hexamethylenetetramine and Hydrogen?
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Developing simple and green routes to access valuable chemicals is of significance. Herein, we present a green and novel route to synthesize N,N-dimethyl arylmethylamines (DAMAs) from hexamethylenetetramine (HMTA) and aryl aldehydes in the presence of hydrogen, and a series of DAMAs can be obtained in good yields. This approach opens the precedent for HMTA as N,N-dimethylamine source to synthesize chemicals with N,N-dimethylamine group, which has promising applications for N-containing chemicals synthesis.
- Ke, Zhengang,Yu, Bo,Wu, Yunyan,Zhao, Yanfei,Yang, Peng,Guo, Shien,Liu, Zhimin
-
supporting information
p. 842 - 846
(2020/05/14)
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- Reductive Alkylation of Amines with Carboxylic Ortho Esters
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We have demonstrated for the first time that carboxylic ortho esters could be used as an alkylating agent in the reductive alkylation of amines. A variety of amines, including amino acid esters, were alkylated affording mono-alkylated products with high selectivity in practical to high yields using standard heterogeneous catalysts. By applying acyclic ortho esters alkylation was completed at room temperature. (Figure presented.).
- Kadyrov, Renat,Moebus, Konrad
-
supporting information
p. 3352 - 3357
(2020/07/04)
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- Cu2O-catalyzed C–S coupling of quaternary ammonium salts and sodium alkane-/arene-sulfinates
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A new protocol for the synthesis of (enantioenriched) benzylic sulfones via the Cu2O-catalyzed C–S bond cross coupling of alkane-/arene-sulfinates and (enantioenriched) benzylic quaternary ammonium salts has been developed. The product benzylic sulfones were obtained in good to high yields (75–96%). Chiral arylmethyl sulfones with high enantiomeric excess (90–94% ee) were also synthesized in the presence of Cu2O and 1,1′-bis-(diphenylphosphino)ferrocene (dppf).
- Chen, Hongyi,Huang, Youming,Zeng, Qingle,Zheng, Wenting
-
supporting information
(2020/08/28)
-
- UiO-type metal-organic frameworks with NHC or metal-NHC functionalities for: N-methylation using CO2 as the carbon source
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We demonstrate the first metal-organic framework (MOF) that catalyzes N-methylation of amines using 1 atm CO2 and phenylsilane under ambient conditions. Compared with its homogeneous analog, the incorporation of N-heterocyclic carbene (NHC) into the MOF provides more efficient catalysis with improved reaction kinetics, turnover numbers and recyclability. Moreover, the metalated NHC functionalized MOF achieves direct N-methylation of amines bearing carboxylate moieties, which are common building blocks in pharmaceutical chemistry.
- Zhang, Xu,Jiang, Yilin,Fei, Honghan
-
supporting information
p. 11928 - 11931
(2019/10/11)
-
- Mn-Catalyzed Selective Double and Mono-N-Formylation and N-Methylation of Amines by using CO2
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Functionalization of amines by using CO2 is of fundamental importance considering the abundance of amines and CO2. In this context, the catalytic formylation and methylation of amines represent convenient and successful protocols for selective CO2 utilization as a C1 building block. This study represents the first example of selective catalytic double N-formylation of aryl amines by using a dinuclear Mn complex in the presence of phenylsilane. This robust system also allows for selective formylation and methylation of amines under a range of conditions.
- Huang, Zijun,Jiang, Xiaolin,Zhou, Shaofang,Yang, Peiju,Du, Chen-Xia,Li, Yuehui
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p. 3054 - 3059
(2019/04/10)
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- Fast continuous alcohol amination employing a hydrogen borrowing protocol
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A continuous flow method for the direct conversion of alcohols to amines via a hydrogen borrowing approach is reported. The method utilises a low loading (0.5%) of a commercial catalyst system ([Ru(p-cymene)Cl2]2 and DPEPhos), reagent grade solvent and is selective for primary alcohols. Successful methylation of amines using methanol and the direct dimethylamination of alcohols using commercial dimethylamine solution are reported. The synthesis of two pharmaceutical agents Piribedil (5) and Buspirone (25) were accomplished in good yields employing these new methods.
- Labes, Ricardo,Mateos, Carlos,Battilocchio, Claudio,Chen, Yiding,Dingwall, Paul,Cumming, Graham R.,Rincón, Juan A.,Nieves-Remacha, Maria José,Ley, Steven V.
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supporting information
p. 59 - 63
(2019/01/11)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
-
supporting information
(2019/05/22)
-
- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
-
supporting information
p. 6084 - 6093
(2019/05/24)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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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.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Heterogeneous Catalytic Reduction of Tertiary Amides with Hydrosilanes Using Unsupported Nanoporous Gold Catalyst
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We have demonstrated that the unsupported nanoporous gold (AuNPore) was a green and highly efficient heterogeneous catalyst for the reduction of amides to amines using hydrosilanes as reductants. A variety of tertiary amides with a broad functional groups were reduced to the corresponding tertiary amines in the presence of 2 mol% of AuNPore and PheMe2SiH or (Me2SiH)2O under mild conditions. AuNPore catalyst was recovered by simple filtration and used for twelve times without any loss of catalytic activity. The AuNPore/hydrosilane system was also successfully applied to the hydrosilative reduction of sulfoxides and N-oxides. (Figure presented.).
- Zhao, Yuhui,Zhang, Sheng,Yamamoto, Yoshinori,Bao, Ming,Jin, Tienan,Terada, Masahiro
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supporting information
p. 4817 - 4824
(2019/10/28)
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- Hydrosilylative Reduction of Tertiary Amides to Amines Catalyzed by N-(Phosphinoaryl)anilido Complexes of Iron and Cobalt
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The synthesis and structural characterization of low-coordinate Fe(II) and Co(II) complexes supported by the monoanionic P,N-ligand N-(2-dicyclohexylphosphinophenyl)-2,6-diisopropylanilide are described. A three-coordinate (P,N)Fe-hexamethyldisilazide complex (2), and four-coordinate (P,N)Fe- (3-Fe) and (P,N)Co-alkyl (3-Co) complexes were evaluated as pre-catalysts for the hydrosilylative reduction of amides with PhSiH3 (5 mol % pre-catalyst, 1 equiv. PhSiH3, 80 °C, 1–24 h). The Fe complex 2 proved to be more broadly effective for the reduction of a variety of tertiary amide substrates, and was shown to mediate the reduction of N,N-dibenzylbenzamide at a loading of 1 mol %, to achieve near quantitative formation of tribenzylamine in 1 h (80 °C). Complex 2 also proved effective for the hydrosilylation of tertiary amides under ambient conditions (5 mol % Fe, 24 h), which is a unique example of room temperature amide hydrosilylation mediated by an Fe catalyst without the need for photochemical activation. Given the widespread use of amide reduction protocols in synthesis, the development of efficient Fe-based catalysts that operate under mild conditions is an important target.
- Hale, Dylan J.,Murphy, Luke J.,McDonald, Robert,Ferguson, Michael J.,Turculet, Laura
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p. 3818 - 3827
(2019/06/17)
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- Bench-Stable Cobalt Pre-Catalysts for Mild Hydrosilative Reduction of Tertiary Amides to Amines and Beyond
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The readily synthesized and bench-stable cobalt dichloride complex (dpephos)CoCl2 is employed as a pre-catalyst for a diversity of silane additions to unsaturated organic molecules, including the normally challenging reduction of amides to amines. With regard to hydrosilative reduction of amides even more effective and activator free catalytic systems can be generated from the bench-stable, commercially available Co(acac)2 and Co(OAc)2 with dpephos and PPh3 ligands. These systems operate under mild conditions (100 °C), with many examples of room temperature transformations, presenting a first example of mild cobalt-catalyzed hydrosilylation of amides.
- Nurseiit, Alibek,Janabel, Jaysan,Gudun, Kristina A.,Kassymbek, Aishabibi,Segizbayev, Medet,Seilkhanov, Tulegen M.,Khalimon, Andrey Y.
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p. 790 - 798
(2019/01/09)
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- Method for preparing tertiary amine organic compounds by using substituted formamide
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The invention discloses a method for preparing tertiary amine organic compounds by using substituted formamide. According to the method, aldehyde is used as a reaction substrate, substituted formamideis used as a solvent, reducing agent and aminating agent, a metal oxide/hydroxide is added as a catalyst, and a small amount of water is added as an auxiliary agent; heating and stirring are carriedout so as to form corresponding tertiary amine compounds; and a reaction can be conducted only through heating without hydrogen and a reducing agent. The method of the invention is applicable to various aldehydes including aromatic aldehydes, fatty aldehydes, etc., and has the characteristics of few by-products and high product yield; and hydrogen is not used in the reaction, and the use of a noble metal hydrogenation catalyst is avoided, so the method has remarkable technical and economic effects and application prospects.
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Paragraph 0020-0022; 0036-0038; 0042-0044
(2019/01/24)
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- Ni-Catalyzed C-P Coupling of Aryl, Benzyl, or Allyl Ammonium Salts with P(O)H Compounds
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A methodology that allows for the construction of C-P bonds via the nickel-catalyzed cross-coupling of organoammonium salts with appropriate phosphorus nucleophiles has been developed. Aryl-, pyridyl-, benzyl-, and allyl-ammonium triflates can be employed as the electrophiles. The employed phosphorus-based nucleophiles included diaryl/dibutyl phosphine oxide, dialkyl phosphonates, and ethyl phenylphosphinate. Functional groups OMe, CN, CF3, F, Cl, C(O)NMe2, and C(O)tBu were tolerated.
- Yang, Bo,Wang, Zhong-Xia
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p. 1500 - 1509
(2019/02/07)
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- Selective formylation or methylation of amines using carbon dioxide catalysed by a rhodium perimidine-based NHC complex
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Carbon dioxide can play a vital role as a sustainable feedstock for chemical synthesis. To be viable, the employed protocol should be as mild as possible. Herein we report a methodology to incorporate CO2 into primary, secondary, aromatic or alkyl amines catalysed by a Rh(i) complex bearing a perimidine-based NHC/phosphine pincer ligand. The periminide-based ligand belongs to a class of 6-membered NHC ligand accessed through chelate-assisted double C-H activation. N-Formylation and -methylation of amines were performed using a balloon of CO2, and phenylsilane as the reducing agent. Product selectivity between formylated and methylated products was tuned by changing the solvent, reaction temperature and the quantity of phenylsilane used. Medium to excellent conversions, as well as tolerance to a range of functional groups, were achieved. Stoichiometric reactions with reactants employed in catalysis and time course studies suggested that formylation and methylation reactions of interest begin with hydrosilylation of CO2 followed by reaction with amine substrates.
- Lam, Raphael H.,McQueen, Caitlin M. A.,Pernik, Indrek,McBurney, Roy T.,Hill, Anthony F.,Messerle, Barbara A.
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p. 538 - 549
(2019/02/14)
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- Biomass-derived N-doped porous carbon: An efficient metal-free catalyst for methylation of amines with CO2
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Developing green, efficient, and low-cost catalysts for methylation of N-H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the CO bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N-H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource.
- Tang, Feiying,Wang, Liqiang,Liu, You-Nian
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supporting information
p. 6252 - 6257
(2019/12/03)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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