- Cobalt-Catalyzed Deoxygenative Hydroboration of Nitro Compounds and Applications to One-Pot Synthesis of Aldimines and Amides
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The commercially available and bench-stable Co(acac)2 ligated with bis[(2-diphenylphosphino)phenyl] ether (dpephos) was employed for selective room temperature hydroboration of nitro compounds with HBPin (TOF up to 4615 h?1), tolerating halide, hydroxy, amino, ether, ester, lactone, amide and heteroaromatic functionalities. These reactions offered a direct access to a variety of N-borylamines RN(H)BPin, which were in situ treated with aldehydes and carboxylic acids to produce a series of aldimines and secondary carboxamides without the need for dehydrating and/or coupling reagents. Combination of these transformations in a sequential one-pot manner allowed for direct and selective synthesis of aldimines and secondary carboxamides from readily available and inexpensive nitro compounds.
- Gudun, Kristina A.,Zakarina, Raikhan,Segizbayev, Medet,Hayrapetyan, Davit,Slamova, Ainur,Khalimon, Andrey Y.
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p. 601 - 611
(2021/11/30)
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- Sulfated polyborate: A dual catalyst for the reductive amination of aldehydes and ketones by NaBH4
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An efficient, quick, and environment-friendly one-pot reductive amination of aldehydes or ketones was developed. In ethanol at 70 °C, a imination catalyzed by sulfated polyborate and further reduced by sodium borohydride yields various amines. The present method has many significant benefits, including a shorter reaction time, excellent yields, and a hassle-free, straightforward experimental process. The reaction has a wide range of applications due to its flexibility, including secondary amine for reductive amination.
- Ganwir, Prerna,Chaturbhuj, Ganesh
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supporting information
(2021/05/19)
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- Synthesis of β-Phosphinolactams from Phosphenes and Imines
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Various cis-β-phosphinolactams are synthesized stereoselectively for the first time from imines and diazo(aryl)methyl(diaryl)phosphine oxides under microwave irradiation. Diazo(aryl)methyl(diaryl)phosphine oxides first undergo the Wolf rearrangement to generate phosphenes. Imines nucleophilically attack the phosphenes followed by an intramolecular nucleophilic addition via less steric transition states to give final cis-β-phosphinolactams. C-Styrylimines generally give rise to β-phosphinolactams in higher yields than C-arylimines. The stereoselectivity and proposed mechanism are rationalized by DFT theoretical calculation.
- Fu, Xingyang,Li, Xinyao,Xu, Jiaxi
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supporting information
p. 8733 - 8737
(2021/11/17)
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- Ex-vivo antimalarial and in-vitro biological activities of newly synthesized co(ii) complex with schiff base
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The first-row transition metal complex of Schiff base has been synthesized and characterized based on physicochemical spectral and biochemical methods. The metal-ligand stoichiometry and molecular formula of the complex assessed by Elemental analysis and
- Veeravel,Rajasekar,Balasubramaniyan,Selvarani
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p. 4191 - 4195
(2021/07/31)
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- A Sustainable Palladium-Intercalated Montmorillonite Clay Catalytic System for Imine Hydrogenation under Mild Conditions
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A series of palladium nanoparticles (Pd NPs) intercalated montmorillonite clay catalysts is reported for hydrogenation of 3-diphenyl prop-2-en-1-imine under mild reaction conditions. Pd/clay catalyst was prepared by a simple wet-impregnation method, and t
- Gupta, Unnati,Krishnapriya,Sharma, Rakesh K
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p. 540 - 548
(2020/12/25)
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- Synthesis, characterization, molecular structure and computational study of tetrahedral pentamethylcyclopentadienyl iridacycle complexes with α,β-conjugated Schiff base ligands
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Due to the excellent catalytic activities and phosphorescent properties that iridium complexes display, iridium chemistry has been of great interest for scientific investigation over the past 30 years. Iridium metallacycle analogues (also known as an iridacycles) bearing phenylpyridine (ppy) ligands have been well reported on, whilst complexes with R-phenyl-(3-R-phenylallylidene)amine, which is an α,β-conjugated Schiff base ligand, have not had the same attention, despite the fact that both ligands share a similar coordination mode. In this research, four pentamethylcyclopentadienyl iridacycle complexes, Ir1a-Ir1d, with different α,β-conjugated Schiff base ligands were synthesized from a di-μ-chloro-dichloro-bis-(η5-pentamethylcyclopentadienyl)diiridium(III) precursor. The iridacycle complexes were characterized using spectroscopic techniques and the molecular structures of Ir1ab-Ir1d were determined using X-ray crystallography. The X-ray results revealed that the iridacycle complexes have a tetrahedral geometry, the iridium centre being coordinated through the N[dbnd]C[sbnd]Cα[dbnd]Cβ moiety of the α,β-conjugated Schiff base ligand. Computational calculations with the B3LYP method and with LanL2DZ basis sets indicated that the HOMO-LUMO energy gaps Ir1b-Ir1d were in the range 3.31–3.36 eV. The OMe substituent at the C terminal has a greater impact on the HOMO energy level than the one at the N terminal.
- Daud, Adibah Izzati,Khairul, Wan M.,Liu, Zhi-Qiang,Ong, Kok Tong,Tay, Meng Guan
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- Cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ
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A cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ is reported, which uses nonmetallic quinone DDQ as an oxidant in the allylation of N-benzylanilines under mild conditions. C–C bond with high selectivity and activity was constructed in this reaction and homoallylic amines were obtained with yields of up to 99%.
- Xiong, Ruimei,Hussain, Muhammad Ijaz,Liu, Qing,Xia, Wen,Xiong, Yan
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supporting information
(2019/12/11)
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- Synthesis, Cytotoxicity and Antimicrobial Evaluation of New Coumarin-Tagged β-Lactam Triazole Hybrid
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A series of coumarin-tagged β-lactam triazole hybrids (10a–10o) were synthesized and tested for their cytotoxic activity against MDA-MB-231 (triple negative breast cancer), MCF-7 (estrogen receptor positive breast cancer (ER+)) and A549 (human lung carcinoma) cancer cell lines including one normal cell line, HEK-293 (human embryonic kidney). Two compounds 10b and 10d exhibited substantial cytotoxic effect against MCF-7 cancer cell lines with IC50 values of 53.55 and 58.62 μm, respectively. More importantly, compounds 10b and 10d were non-cytotoxic against HEK-293 cell lines. Structure–activity relationship (SAR) studies suggested that the nitro and chloro group at the C-3 position of phenyl ring are favorable for anticancer activity, particularly against MCF-7 cell lines. Furthermore, antimicrobial evaluation of these compounds revealed modest inhibition of examined pathogenic strains with compounds 10c and 10i being the most promising antimicrobial agents against Pseudomonas aeruginosa and Candida albicans, respectively.
- Awolade, Paul,Cele, Nosipho,Dhawan, Sanjeev,Jonnalagadda, Sreekantha B.,Kaur, Mandeep,Kisten, Prishani,Pillay, Ashona-Singh,Saha, SouravTaru,Singh, Parvesh
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- Ruthenium N-Heterocyclic Carbene Complexes for Chemoselective Reduction of Imines and Reductive Amination of Aldehydes and Ketones
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Chemoselective reduction of imines to secondary amines is catalyzed efficiently by tethered and untethered, half-sandwich ruthenium N-heterocyclic carbene (NHC) complexes at room temperature. The untethered Ru-NHC complexes are more efficient as catalysts for the reduction of aldimines and ketimines than the tethered complexes. Using the best untethered complex as a catalyst, electronic and steric demands on the reaction was probed using a series of imines. Chemoselectivity of the catalyst towards imine reduction was tested by performing inter and intramolecular competitive reactions in a variety of ways. The catalyst exhibits a very high TON and TOF under anaerobic conditions.
- Kathuria, Lakshay,Samuelson, Ashoka G.
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supporting information
(2020/06/17)
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- Catalyst- And solvent-free efficient access to: N -alkylated amines via reductive amination using HBpin
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A sustainable approach which works under catalyst- and solvent-free conditions for the synthesis of structurally diverse secondary amines has been uncovered. This one-pot protocol works efficiently at room temperature and is compatible with a wide range of sterically and electronically diverse aldehydes and primary amines. Notably, this simple process offers scalability, excellent functional group tolerance, chemoselectivity, and is also effective at the synthesis of biologically relevant molecules. This journal is
- Bauri, Somnath,Pandey, Vipin K.,Rit, Arnab
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supporting information
p. 3853 - 3857
(2020/07/27)
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- Stereoselective Construction of γ-Lactams via Copper-Catalyzed Borylacylation
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A versatile and highly stereoselective borylative cyclization to generate polyfunctionalized γ-lactams has been developed. The stereoselective synthesis of these key ring systems is crucial due to their ubiquity in natural products. We report the diastero- and enantioselective construction of di- and trisubstituted γ-lactam cores, with examples containing an enantioenriched quaternary carbon.
- Bajohr, Jonathan,Lautens, Mark,Polishchuk, Iuliia,Torelli, Alexa,Whyte, Andrew
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supporting information
p. 7915 - 7919
(2020/11/02)
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- Superacid-promoted synthesis of quinoline derivatives
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A series of vinylogous imines have been prepared from anilines and cinnamaldehydes. These substrates react in superacidic media to provide quinolines and related compounds. A mechanism for the conversion is proposed which involves the cyclization of dicationic superelectrophilic intermediates. Aromatization of the quinoline ring is thought to occur by superacid-promoted elimination of benzene.
- Klumpp, Douglas A.,Stentzel, Michael R.,Vuong, Hein
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supporting information
(2020/01/24)
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- Cu/Ni-doped sulfated zirconium oxide immobilized on CdFe2O4 NPs: a cheap, sustainable and magnetically recyclable inorgano-catalyst for the efficient preparation of α-aminonitriles in aqueous media
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Abstract: A new multifunctional bimetallic nanocatalyst was prepared by immobilization of Cu/Ni-doped sulfated zirconium oxide on magnetic cadmium ferrite (CdFe2O4@SiO2@ZrO2/SO42?/Cu/Ni) and used as an efficient recyclable catalyst for one-pot as well as stepwise preparation of α-aminonitriles under mild conditions. The magnetic nanocatalyst was characterized by FTIR, TGA, VSM, XRD, EDX, FE-SEM, and TEM analyses. Also, the surface acidity of the catalyst was measured by pyridine adsorption assay. The catalyst possesses various active sites which could catalyst a variety of aromatic and aliphatic aldehydes to the corresponding α-amionitriles under moderate to high yields in the presence of aniline. Furthermore, transformation of ketones to the desired α-amionitriles and some bis-aminonitriles was also performed by this method. The catalyst could be readily recovered from the reaction mixture and reused for several times without significant loss of activity. Graphic abstract: A general and efficient method has been developed for transformation of a variety of aliphatic, aromatic aldehydes and ketones to the corresponding α-aminonitriles using a multifunctional recyclable CdFe2O4@SiO2@ZrO2/SO42?/Cu/Ni nanocatalyst.[Figure not available: see fulltext.]
- Nasseri, Mohammad Ali,Ramezani-Moghadam, Simin,Kazemnejadi, Milad,Allahresani, Ali
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p. 4233 - 4256
(2020/07/08)
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- Switching the N-Alkylation of Arylamines with Benzyl Alcohols to Imine Formation Enables the One-Pot Synthesis of Enantioenriched α-N-Alkylaminophosphonates
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The selective N-alkylation of anilines with benzylic alcohols can be switched in favor of the dehydrogenative condensation process using the nitrile-ligated Kn?lker's complex by conducting the reaction either in a closed system under inert conditions, or in an open system in air. The selective formation of imines, containing reactive C=N bonds, provides an opportunity towards further functionalization. Indeed, a one-pot three-component condensation of alcohols, amines and phosphites, promoted by an iron-based Kn?lker-type complex in combination with a chiral BINOL-based phosphoric acid, provides access to enantioenriched α-N-alkylaminophosphonates.
- Hofmann, Natalie,Hultzsch, Kai C.
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supporting information
p. 3105 - 3111
(2019/06/08)
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- Promoting Frustrated Lewis Pairs for Heterogeneous Chemoselective Hydrogenation via the Tailored Pore Environment within Metal–Organic Frameworks
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Frustrated Lewis pairs (FLPs) have recently been advanced as efficient metal-free catalysts for catalytic hydrogenation, but their performance in chemoselective hydrogenation, particularly in heterogeneous systems, has not yet been achieved. Herein, we demonstrate that, via tailoring the pore environment within metal–organic frameworks (MOFs), FLPs not only can be stabilized but also can develop interesting performance in the chemoselective hydrogenation of α,β-unsaturated organic compounds, which cannot be achieved with FLPs in a homogeneous system. Using hydrogen gas under moderate pressure, the FLP anchored within a MOF that features open metal sites and hydroxy groups on the pore walls can serve as a highly efficient heterogeneous catalyst to selectively reduce the imine bond in α,β-unsaturated imine substrates to afford unsaturated amine compounds.
- Niu, Zheng,Zhang, Weijie,Lan, Pui Ching,Aguila, Briana,Ma, Shengqian
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supporting information
p. 7420 - 7424
(2019/04/27)
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- Development of Chiral Spiro Phosphoramidites for Rhodium-Catalyzed Enantioselective Reactions
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A series of 1,1′-spirobiindane-7,7′-diol (SPINOL) analogues bearing a 2,2′-dimethyl-, cyclopentyl-, or cyclohexyl-fused ring were synthesized, and their distinct structural features were elucidated by X-ray crystallography. On the basis of these scaffolds, chiral monophosphoramidite ligands 6 a–m were synthesized, which demonstrated excellent enantioselectivity in RhI-catalyzed asymmetric hydrogenation of a dehydro amino acid methyl ester. Ligands 6 a–m were also successfully applied in the RhI-catalyzed enantioselective [4+2] cycloaddition of α,β-unsaturated imines with isocyanates, which afforded the corresponding pyrimidinones in good yields (60–92 %) with high enantioselectivities (75–92 % ee).
- Zheng, Zhiyao,Cao, Yuxi,Zhu, Dongsheng,Wang, Zheng,Ding, Kuiling
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supporting information
p. 9491 - 9497
(2019/04/08)
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- Bi-functional catalyst of porous N-doped carbon with bimetallic FeCu for solvent-free resultant imines and hydrogenation of nitroarenes
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The efficient and stable catalyst applied to the transformation of amines into the corresponding imines and hydrogenation of nitroarenes under mild reaction conditions is reported. The catalytic performance of porous N-doped carbon with FeCu (FeCu@NPC) catalyst are tested by aromatic alcohol-based N-alkylated of amines with solvent-free and hydrogenation of nitroarenes via N2H4·H2O. The results proved that the yield of these two reactions are all over 99.9% under optimum condition. Moreover, the synergistic effect of the catalyst for N-alkylated reaction was investigated through the kinetic study. The catalyst can be easily separated from reaction system by an external magnetism, and can be recycled and reutilized for at least 4 runs with conversions are all over 75%. The study of the catalyst indicated that it was suitable for the reactions in industry. Hence, the catalysis process by the inexpensive metals-based catalyst is green and sustainable.
- Wang, Kaizhi,Gao, Wenbing,Jiang, Pengbo,Lan, Kai,Yang, Ming,Huang, Xiaokang,Ma, Lei,Niu, Fang,Li, Rong
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- The preparation and photocatalytic activity of Ag-Pd/g-C3N4 for the coupling reaction between benzyl alcohol and aniline
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In this study, the carrier g-C3N4 was prepared by melamine, and the Ag-Pd/g-C3N4 catalyst was synthesized by the NaBH4 reduction method. Different characterization techniques, including SEM, TEM, XRD, UV–vis DRS, XPS, photoluminescence spectra (PL) and BET, were employed to investigate the morphology and optical properties of the as-prepared samples. The Ag-Pd/g-C3N4 catalyst was used for the synthesis of imine from a benzyl alcohol and aniline. The results show that when the total loading of Ag and Pd is 2 wt%, and the mass ratio of Ag and Pd is 1:1, the activity of the catalyst is the highest (The highest conversion of aniline is 86.7% and the product selectivity is >99%.). The reaction is optimized by changing the type of solvent, the type and amount of base, the type of catalyst, and the amount of reactants. The optimal reaction conditions are 6 ml of n-hexane, 1.4 mmol of Cs2CO3, 50 mg of the Ag-Pd/g-C3N4 (2 wt%, 1:1), and 2:1 mol ratio of benzyl alcohol and aniline. Under optimal reaction conditions, alcohol derivatives and amine derivatives were investigated to determine the suitable range of the catalyst for alcohols and amines. Then, the effects of different light intensities and wavelengths on the reaction were explored. Additionally, the catalyst's recycling ability was tested, and it was found to be relatively stable. The effect of reactive groups on the mechanism shows that the reaction is mainly achieved by the synergy between h+, e? and ·O2?.
- Ma, Jingjing,Yu, Xiujuan,Liu, Xiaoling,Li, Haiying,Hao,Li, Jingyi
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- Silylative Reductive Amination of α,β-Unsaturated Aldehydes: A Convenient Synthetic Route to β-Silylated Secondary Amines
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Described here is a reductive amination/hydrosilylation cascade of α,β-unsaturated aldehydes mediated by a Lewis acidic borane catalyst. The present reaction system provides an one-pot synthetic route towards β-silylated secondary amines that have not been accessible by other previous catalysis. Comparative 1H NMR studies on the silylative reduction of enimines revealed that steric bulkiness of primary amine reactants strongly affects both catalytic efficiency and regioselectivity. This strategy was applicable to a broad range of substrates and amenable to one-pot gram-scale synthesis. Moreover, a diastereoselective introduction of the β-silyl group was also found to be feasible (d.r. up to 71:29).
- Kim, Eunae,Park, Sehoon,Chang, Sukbok
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supporting information
p. 5765 - 5769
(2018/03/28)
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- Synthesis of azomethines derived from cinnamaldehyde and vanillin: in vitro aetylcholinesterase inhibitory, antioxidant and insilico molecular docking studies
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In the present study, we report the synthesis of azomethines derived from cinnamaldehyde (C1–C3) and vanillin (V1–V3) using ethanol as a green solvent in the presence of triethyl amine. The synthesized compounds were characterized and investigated for the
- Chigurupati, Sridevi,Selvaraj, Manikandan,Mani, Vasudevan,Mohammad, Jahidul I.,Selvarajan, Kesavanarayanan K.,Akhtar, Shaikh S.,Marikannan, Maharajan,Raj, Suthakaran,Teh, Lay K.,Salleh, Mohd Z.
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p. 807 - 816
(2017/11/16)
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- Manganese catalyzed reductive amination of aldehydes using hydrogen as a reductant
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A one-pot two-step procedure was developed for the alkylation of amines via reductive amination of aldehydes using molecular dihydrogen as a reductant in the presence of a manganese pyridinyl-phosphine complex as a pre-catalyst. After the initial condensation step, the reduction of imines formed in situ is performed under mild conditions (50-100 °C) with 2 mol% of catalyst and 5 mol% of tBuOK under 50 bar of hydrogen. Excellent yields (>90%) were obtained for a large combination of aldehydes and amines (40 examples), including aliphatic aldehydes and amino-alcohols.
- Wei, Duo,Bruneau-Voisine, Antoine,Valyaev, Dmitry A.,Lugan, No?l,Sortais, Jean-Baptiste
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supporting information
p. 4302 - 4305
(2018/05/03)
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- First example of the cascade acylation/IMDAV/ene reaction sequence, leading to N-arylbenzo[f]isoindole-4-carboxylic acids possessing anti-viral activity
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The reaction between readily accessible N-aryl-3-phenylallylamines and maleic anhydride led to unexpected products – polysubstituted hydrogenated benzo[f]isoindole-4-carboxylic acids. This transformation proceeds through a previously unknown sequence of s
- Voronov, Alexander A.,Alekseeva, Kseniia A.,Ryzhkova, Elena A.,Zarubaev, Vladimir V.,Galochkina, Anastasia V.,Zaytsev, Vladimir P.,Majik, Mahesh S.,Tilve, Santosh G.,Gurbanov, Atash V.,Zubkov, Fedor I.
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supporting information
p. 1108 - 1111
(2018/03/06)
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- The Divergent Cascade Reactions of Arylalkynols with Homopropargylic Amines or Electron-Deficient Olefins: Access to the Spiro-Isobenzofuran- b-pyrroloquinolines or Bridged-Isobenzofuran Polycycles
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Two divergent cascade reactions of arylalkynols with homopropargylic amines or electron-deficient olefins were developed to synthesize the spiro-isobenzofuran-b-pyrroloquinolines or bridged-isobenzofuran heterocycles in good yields, respectively. One reaction actually involved intramolecular 5-endo-dig hydroamination cyclization-protonation of homopropargylic amines to give cycloiminium ions and intramolecular 5-exo-dig hydroalkoxylation cyclization of arylalkynols to generate isobenzofuran with exocyclic double bond, followed by the nontypical Povarov-type reaction in the presence of PtCl2/FeCl3 cocatalysts. The other underwent intramolecular hydroalkoxylation cycloisomerization of alkynols with the subsequent normal [4 + 2] cycoaddition with dienophiles. Herein, the arylalkynols acted as both "masked" electron-rich olefins and "masked" electron-rich dienes.
- Wang, Lun,Liu, Lingyan,Chang, Weixing,Li, Jing
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supporting information
p. 7799 - 7813
(2018/06/18)
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- Stabilized Ru[(H2O)6]3+ in Confined Spaces (MOFs and Zeolites) Catalyzes the Imination of Primary Alcohols under Atmospheric Conditions with Wide Scope
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Imines are ubiquitous intermediates in organic synthesis, and the metal-mediated imination of alcohols is one of the most direct and simple methods for their synthesis. However, reported protocols lack compatibility with many other functional groups since basic supports/media, pure oxygen atmospheres, and/or released hydrogen gas are required during reaction. Here we show that, in contrast to previous metal-catalyzed methods, hexa-aqueous Ru(III) catalyzes the imination of primary alcohols with very wide functional group tolerance, at slightly acid pH and under low oxygen atmospheres. The inorganic metal complex can be supported and stabilized, integrally, within either faujasite-type zeolites (Y and X) or a metal organic framework (MOF), to give a reusable heterogeneous catalyst which provides an industrially viable process well below the flammability limit of alcohols and amines.
- Mon, Marta,Adam, Rosa,Ferrando-Soria, Jesús,Corma, Avelino,Armentano, Donatella,Pardo, Emilio,Leyva-Pérez, Antonio
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p. 10401 - 10406
(2018/10/24)
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- Synthesis of quinoline derivatives from anilines and aldehydes catalyzed by Cp2ZrCl2 and recyclable Cp2ZrCl2/MCM-41 system
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A facile method for the synthesis of quinoline derivatives using catalytic amount of Cp2ZrCl2 or Cp2ZrCl2 supported on MCM-41 (Cp2ZrCl2/MCM-41) in reaction of anilines and aldehydes is described. When Cp2ZrCl2/MCM-41 was used as catalyst, the yields of quinolines were enhanced by 5-15% compared with Cp2ZrCl2 as catalyst alone under the same reaction conditions. More importantly, Cp2ZrCl2/MCM-41 catalyst can be reused at least thrice by simple recover via filtration in air. Moreover, both Cp2ZrCl2 and Cp2ZrCl2/MCM-41 showed good catalytic activities to generate corresponding quinoline derivatives in moderate to good yields by varying the substituent of aniline and aldehyde. And the reaction conditions were optimized by studying the influences of reactant ratio, additives, solvent effect and reaction temperatures.
- Guo, Qiaoxia,Liao, Lijun,Teng, Weiling,Ren, Shenyong,Wang, Xiao,Lin, Yingying,Meng, Fanfang
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p. 117 - 122
(2016/02/03)
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- Enantioselective and Regiodivergent Functionalization of N-Allylcarbamates by Mechanistically Divergent Multicatalysis
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A pair of mechanistically divergent multicatalytic reaction sequences has been developed consisting of nickel-catalyzed isomerization of N-allylcarbamates and subsequent phosphoric-acid-catalyzed enantioselective functionalization of the resulting intermediates. By appropriate selection of reaction partners, in situ generated imines and ene-carbamates are mechanistically partitioned to yield opposing functionalized products. Formal α-functionalization to give protected α-arylamines is achieved upon enantioselective Friedel–Crafts reaction with arene nucleophiles, whereas formal β-functionalization is achieved upon reaction with diarylimine electrophiles in an enantioselective Povarov-[4+2] cycloaddition.
- Richmond, Edward,Khan, Ismat Ullah,Moran, Joseph
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supporting information
p. 12274 - 12277
(2016/08/24)
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- Modular access to vicinally functionalized allylic (thio)morpholinonates and piperidinonates by substrate-controlled annulation of 1,3-azadienes with hexacyclic anhydrides
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A modular substrate-controlled hexannulation of inherently promiscuous 1,3-azadienes with hexacyclic anhydrides, which affords versatile vicinally functionalized allylic lactams, in high yields, regio- and stereoselectivities is described.
- Braunstein, Hannah,Langevin, Spencer,Khim, Monique,Adamson, Jonathan,Hovenkotter, Katie,Kotlarz, Lindsey,Mansker, Brandon,Beng, Timothy K.
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supporting information
p. 8864 - 8872
(2016/10/03)
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- Mesoporous carbon derived from Vitamin B12: A high-performance bifunctional catalyst for imine formation
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Mesoporous carbon derived from natural vitamin B12 is applied for the first time in organic synthesis and exhibits exceptionally high dual activity for imine formation via the cross-coupling of alcohols with amines and the self-coupling of primary amines using molecular oxygen or air as the terminal oxidant.
- Chen, Bo,Shang, Sensen,Wang, Lianyue,Zhang, Yi,Gao, Shuang
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supporting information
p. 481 - 484
(2016/01/12)
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- Load manganese oxidizing catalytic chipboard spreading method for one-step synthesis of imines
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The invention belongs to the technical fields of chemistry and chemical engineering, and concretely relates to a method for one step synthesis of imine through catalyzing alcohol and amine by supported manganese oxide. A reaction of alcohol and amine is carried out in a solvent or solvent-free state at 60-90DEG C for 6-48h with the supported manganese oxide as a catalyst and molecular oxygen or air as an antioxidant to realize one step synthesis of a corresponding imine compound. The valence of manganese in the catalyst is +2, +3 or +4, the general formula of the catalyst is MnOx, and a carrier is hydroxyapatite (Ca10(PO4)6(OH)2). The catalyst still has very good activity and selectivity after the catalyst is reused at least 9 times. The catalyst used in the method has the characteristics of simple preparation, cheapness, high reaction selectivity and environmental protection.
- -
-
Paragraph 0040; 0041
(2017/02/02)
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- Synthesis of Tetrasubstituted Pyrroles from Homopropargylic Amines via a Sonogashira Coupling/Intramolecular Hydroamination/Oxidation Sequence
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A one-pot reaction of homopropargylic amines and aryl iodides was developed in the presence of a palladium (Pd) catalyst and generated a series of tetrasubstituted pyrrole derivatives in good to high yields. This process involved a Sonogashira, intramolecular hydroamination, cyclization and oxidation sequence of reactions.
- Wang, Chan,Huang, Kaimeng,Wang, Junying,Wang, Hongkai,Liu, Lingyan,Chang, Weixing,Li, Jing
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supporting information
p. 2795 - 2802
(2015/09/28)
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- Zn-Catalyzed Enantio- and Diastereoselective Formal [4 + 2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitro-Alkenes
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We report a catalytic asymmetric synthesis of piperidines through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to be particularly impactful, due to limiting the undesired coordination of 1-azadiene to the Lewis acid and thus allowing the reaction to be carried out at lower temperature. A series of secondary kinetic isotope effect studies using a range of ligands implicates a stepwise mechanism for the transformation, involving an initial Michael-type addition of the imine to the nitro-alkene followed by a cyclization event. The stepwise mechanism obviates the electronic requirement inherent to a concerted mechanism, explaining the successful cycloaddition between two electron-deficient partners. (Chemical Equation Presented).
- Chu, John C. K.,Dalton, Derek M.,Rovis, Tomislav
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supporting information
p. 4445 - 4452
(2015/04/14)
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- Aqueous formic acid: An efficient, inexpensive and environmentally friendly organocatalyst for three-component Strecker synthesis of α-aminonitriles and imines with excellent yields
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Aqueous formic acid (37%) which is an efficient, inexpensive and environmentally friendly organocatalyst was used in the Strecker reaction to afford α-aminonitriles and imines. Reaction was carried out under mild conditions and room temperature in high yi
- Ghafuri, Hossein,Roshani, Mahdi
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p. 58280 - 58286
(2015/02/19)
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- Understanding α,β-unsaturated imine formation from amine additions to α,β-unsaturated aldehydes and ketones: An analytical and theoretical investigation
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A combination of in situ IR spectroscopy (ReactIR) and DFT calculations have been used to understand what factors govern the selectivity in the addition of primary amines to α,β-unsaturated aldehydes and ketones, i.e., 1,2- versus 1,4-addition. It has been found that the 1,2-addition products (α,β-unsaturated imines following addition and elimination) usually predominate for most systems. However, exceptions, such as methyl vinyl ketone, selectively give 1,4-addition products. This has been rationalized by DFT calculations that show that major conformational effects are involved, controlled mainly by steric effects of carbonyl substituents, resulting in a model that provides simple and predictable preparation of α,β- unsaturated imines for in situ utilization in synthesis.
- Calow, Adam D. J.,Carbó, Jorge J.,Cid, Jessica,Fernández, Elena,Whiting, Andrew
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supporting information
p. 5163 - 5172
(2014/06/23)
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- Insertion of Nitriles into Zirconocene 1-aza-1,3-diene Complexes: Chemoselective Synthesis of N-H and N-Substituted Pyrroles
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The direct insertion of nitriles into zirconocene-1-aza-1,3-diene complexes provides an efficient, chemoselective, and controllable synthesis of N-H and N-substituted pyrroles upon acidic aqueous work-up. The outcome of the reaction (that is, the formatio
- Yu, Shasha,Xiong, Meijun,Xie, Xin,Liu, Yuanhong
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supporting information
p. 11596 - 11599
(2016/02/19)
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- Selective aerobic oxidation of alcohols to aldehydes, carboxylic acids, and imines catalyzed by a Ag-NHC complex
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Silver NHC catalysts have been developed for the selective oxidation of alcohols to aldehydes or carboxylic acids in the presence of BnMe3NOH or KOH under dry air. The aerobic oxidation conditions are mild, and the yield is excellent. Further tandem catalysis enables the one-pot synthesis of imines in excellent yield. Only 0.1 mol % of the catalyst is required.
- Han, Lei,Xing, Ping,Jiang, Biao
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supporting information
p. 3428 - 3431
(2014/07/21)
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- Direct imine formation by oxidative coupling of alcohols and amines using supported manganese oxides under an air atmosphere
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Manganese oxides loaded on various supports have been prepared and studied for the direct imine formation by oxidative coupling of alcohols and amines. Among the catalysts, hydroxyapatite supported manganese oxides (MnO x/HAP) show the best activity and selectivity for this reaction in the absence of an additional base using air as the environmentally benign terminal oxidant. NH3-/CO2-TPD results show that the amphoteric properties of MnOx/HAP are crucial for this reaction to obtain a satisfactory yield. Various aromatic alcohols and amines are smoothly transformed into the corresponding imines in good to excellent yields. The catalyst is reusable and gives 98% yield of the product in all 9 reuse tests. Compared with the fresh catalyst, the XRD and SEM of the reactivated MnO x/HAP after nine reactions do not show any obvious change. This journal is the Partner Organisations 2014.
- Chen, Bo,Li, Jun,Dai, Wen,Wang, Lianyue,Gao, Shuang
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p. 3328 - 3334
(2014/06/10)
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- Synthesis of-lactams from acids and imines using thiocarbonyldiimidazole
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Thiocarbonyldiimidazole has been found to be an efficient acid activator for the synthesis of-lactams by ketene-imine cycloaddition at room temperature. The experimental procedure is simple and results in excellent yields of the products. All products wer
- Zarei, Maaroof,Karimi-Jaberi, Zahed,Movahedi, Amin
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p. 728 - 734
(2013/01/15)
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- Chitosan: A highly efficient renewable and recoverable bio-polymer catalyst for the expeditious synthesis of α-amino nitriles and imines under mild conditions
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Commercial chitosan-without any post-modification with active Bronsted or Lewis acid centers-was found to be a highly efficient renewable and recoverable bio-polymer catalyst for the rapid and convenient synthesis of α-amino nitriles or imines from aromatic aldehydes and amines under mild reaction conditions at room temperature in high to quantitative yields. The α-amino nitrile derivatives were prepared through the Strecker reaction using trimethylsilyl cyanide (TMSCN) and catalyzed by chitosan as a heterogeneous bifunctional organocatalyst.
- Dekamin, Mohammad G.,Azimoshan, Mojtaba,Ramezani, Leila
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supporting information
p. 811 - 820
(2013/04/10)
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- Preparation of imines by oxidative coupling of benzyl alcohols with amines catalysed by dicopper complexes
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Complexation of 2,7-bis(2-pyridyl)-1,8-naphthyridine (bpnp) with Cu 2O in formic acid under aerobic conditions provided a dicopper complex [Cu2(bpnp)(μ-OH)(HCOO)3] (1). This complex has been characterized by X-ray crystallographic and spectroscopic analysis. With O2 as the oxidant, complex 1 is an efficient catalyst for the oxidative coupling of alcohols with amines or diamines, leading to the corresponding imines or diimines in good to excellent yields. A dicopper complex has been found to be an efficient catalyst for the oxidative coupling of benzyl alcohols with amines or diamines, leading to the corresponding imines or diimines in good to excellent yields without using any organic solvent. Copyright
- Lan, Yung-Syuan,Liao, Bei-Sih,Liu, Yi-Hong,Peng, Shie-Ming,Liu, Shiuh-Tzung
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supporting information
p. 5160 - 5164
(2013/11/06)
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- Solvent-free addition reaction of allylzinc bromide and aldimines
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(Chemical Equation Presented) Barbier-type allylation of aldimines with allylzinc bromide took place rapidly under solvent-free conditions. The procedure is environmentally benign and operationally simple, has good regioselectivity, and gives good to exce
- Zhang, Yumei,Han, Minghu,Yan, Tingli
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body text
p. 2689 - 2693
(2012/07/14)
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- Taking the F out of FLP: Simple lewis acid-base pairs for mild reductions with neutral boranes via borenium ion catalysis
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Discrete three-coordinate borenium salts 1c and 1d are accessed by cooperative Lewis acid-base pair-mediated heterolytic splitting of the B-H bond in pinacolborane by B(C6F5)3DABCO and Ph 3C+/DABCO, respectively. The resulting salts are competent catalysts in the reduction of a broad range of imines and can be generated in situ. Moreover, a mechanistic framework for borenium catalysis based on experimental evidence is proposed. The reaction is suggested to proceed by borenium activation of the imine substrate followed by counterintuitive hydride delivery from HBPin (with the assistance of DABCO) rather than from the HB(C6F5)3- anion, contrary to typical mechanisms of reduction in FLP systems.
- Eisenberger, Patrick,Bailey, Adrian M.,Crudden, Cathleen M.
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supporting information
p. 17384 - 17387
(2013/01/15)
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- Solvent-free synthesis, DNA-topoisomerase II activity and molecular docking study of new asymmetrically N,N′-substituted ureas
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A new series of asymmetrically N,N′-substituted ureas 20-25 was prepared using solvent free conditions, which is an eco-friendly methodology, starting with Schiff bases derived from cinnamaldehyde and p-substituted anilines, which are subsequently submitt
- Andressa, Esteves-Souza,Rodrigues-Santos, Claudio E.,De Nigris Del Cistia, Catarina,Da Silva, Daniel Rosa,Sant'Anna, Carlos Mauricio R.,Echevarria, Aurea
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p. 12882 - 12894
(2013/02/22)
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- A modular approach to α,β-unsaturated N-aryl ketonitrones
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A modular approach to α,β-unsaturated N-aryl ketonitrones has been developed. Specifically, condensation of anilines and enals followed by alkylation of the resulting α,β-unsaturated imines provided N-allyl anilines, which were subjected to oxidation with
- Hood, Tyler S.,Bryan Huehls,Yang, Jiong
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supporting information; experimental part
p. 4679 - 4682
(2012/09/05)
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- General, green, and scalable synthesis of imines from alcohols and amines by a mild and efficient copper-catalyzed aerobic oxidative reaction in open air at room temperature
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A general, green, and scalable synthesis of the useful imines and a,b-unsaturated imines is successfully achieved by a low-loading and powerful, mild and efficient copper-catalyzed aerobic oxidative reaction of alcohols and amines in the open air at room temperature under base- and dehydrating reagent-free conditions. This practical reaction can use air as the economic and green oxidant, tolerates a wide range of substrates, can afford high yields of the target imines on a large scale, and produces water as the only by-product, and thus being the best imination method as yet using alcohols and amines directly.
- Tian, Haiwen,Yu, Xiaochun,Li, Qiang,Wang, Jianxin,Xu, Qing
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supporting information
p. 2671 - 2677,7
(2012/12/12)
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- Highly active and selective synthesis of imines from alcohols and amines or nitroarenes catalyzed by Pd/DNA in water with dehydrogenation
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A direct imination was developed from alcohols and amines under catalysis of Pd/DNA by dehydrogenation without additional oxidant, affording the corresponding imines in moderate to good yields with excellent chemoselectivity. By virtue of the liberated molecular hydrogen, the nitroarenes could also be deoxidized in situ into amines and a one-pot tandem synthesis of imines was achieved from nitroarenes. This heterogeneous catalyst can be recovered and reused at least five times by taking advantage of its water-soluble reversibility. All these conformations were performed smoothly in water under mild conditions, and an atom economical and environmentally benign synthesis was embodied in this imination.
- Tang, Lin,Sun, Huayin,Li, Yunfeng,Zha, Zhenggen,Wang, Zhiyong
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p. 3423 - 3428
(2013/01/16)
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- GREEN SYNTHESIS OF ARYL ALDIMINES USING ETHYL LACTATE
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The present invention relates to a method for preparing aryl aldimines. In particular, the present invention relates to methods of preparing aryl aldimines that uses environmentally friendly solvent systems.
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Page/Page column 4-5
(2011/08/22)
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- Highly regioselective control of 1,2-addition of organolithiums to α,β-unsaturated compounds promoted by lithium bromide in 2-methyltetrahydrofuran: A facile and eco-friendly access to allylic alcohols and amines
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Very high regioselective 1,2-addition of organolithiums to α,α-unsaturated carbonyl-like compounds (ketones, aldehydes, and imines) in the presence of LiBr was achieved by carrying out reactions in the sustainable solvent 2-methyltetrahydrofuran. Excellent yields (in isolated product) of allylic alcohols and allylic amines were recovered under a simple experimental procedure at 0 °C.
- Pace, Vittorio,Castoldi, Laura,Hoyos, Pilar,Sinisterra, José Vicente,Pregnolato, Massimo,Sánchez-Montero, Ma. José
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supporting information; experimental part
p. 2670 - 2675
(2011/04/23)
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- N-heterocyclic carbene and Bronsted acid cooperative catalysis: Asymmetric synthesis of trans -γ-Lactams
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An efficient enantioselective approach to form trans-γ-lactams in up to 99% yield, 93% ee, and >20/1 dr using unactivated imines has been developed. The cyclohexyl-substituted azolium and the weak base sodium o-chlorobenzoate are most suitable for this tr
- Zhao, Xiaodan,Dirocco, Daniel A.,Rovis, Tomislav
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supporting information; experimental part
p. 12466 - 12469
(2011/09/16)
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- Enantioselective rhodium-catalyzed [4 + 2] cycloaddition of α,β-unsaturated imines and isocyanates
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A [4 + 2] cycloaddition of α,β-unsaturated imines and isocyanates catalyzed by a phosphoramidite-rhodium complex provides pyrimidinones in good yields and high enantioselectivities.
- Oberg, Kevin M.,Rovis, Tomislav
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supporting information; experimental part
p. 4785 - 4787
(2011/05/16)
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- Direct and mild palladium-catalyzed aerobic oxidative synthesis of imines from alcohols and amines under ambient conditions
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By ligand, TEMPO, and base screening, we developed a mild and green one-pot imine synthesis from alcohols and amines via a low-loading palladium-catalyzed tandem aerobic alcohol oxidation-dehydrative condensation reaction that can be readily carried out in open air at room temperature.
- Jiang, Lan,Jin, Luolu,Tian, Haiwen,Yuan, Xueqin,Yu, Xiaochun,Xu, Qing
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supporting information; experimental part
p. 10833 - 10835
(2011/11/04)
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