- Iridium-catalyzed hydrogenation of N-heterocyclic compounds under mild conditions by an outer-sphere pathway
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A new homogeneous iridium catalyst gives hydrogenation of quinolines under unprecedentedly mild conditions-as low as 1 atm of H2 and 25 °C. We report air-and moisture-stable iridium(I) NHC catalyst precursors that are active for reduction of a wide variety of quinolines having functionalities at the 2-, 6-, and 8-positions. A combined experimental and theoretical study has elucidated the mechanism of this reaction. DFT studies on a model Ir complex show that a conventional inner-sphere mechanism is disfavored relative to an unusual stepwise outer-sphere mechanism involving sequential proton and hydride transfer. All intermediates in this proposed mechanism have been isolated or spectroscopically characterized, including two new iridium(III) hydrides and a notable cationic iridium(III) dihydrogen dihydride complex. DFT calculations on full systems establish the coordination geometry of these iridium hydrides, while stoichiometric and catalytic experiments with the isolated complexes provide evidence for the mechanistic proposal. The proposed mechanism explains why the catalytic reaction is slower for unhindered substrates and why small changes in the ligand set drastically alter catalyst activity.
- Dobereiner, Graham E.,Nova, Ainara,Schley, Nathan D.,Hazari, Nilay,Miller, Scott J.,Eisenstein, Odile,Crabtree, Robert H.
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- A Novel Ring Expansion Reaction in the Reduction of Benzylic Methoxyamines with Lithium Aluminium Hydride
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Reduction of the N-O bonds of benzylic hydroxylamines with lithium aluminium hydride gives a novel ring expansion reaction that can be explained by a radical mechanism.
- Booth, Susan E.,Jenkins, Paul R.,Swain, Christopher J.
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- Highly enantioselective iridium-catalyzed hydrogenation of quinoline derivatives using chiral phosphinite H8-BINAPO
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The chiral diphosphinite H8-BINAPO derived from H8-BINOL has been used in the Ir-catalyzed asymmetric hydrogenation of quinolines, and high enantioselectivity (up to 97% ee) was obtained. Immobilization of the iridium catalyst in poly(ethylene glycol) dimethyl ether (DMPEG) is also discussed. With DMPEG/hexane biphasic system, better enantioselectivities were obtained as compared to those observed in aprotic organic solvents.
- Kim, Hung Lam,Xu, Lijin,Feng, Lichun,Fan, Qing-Hua,Fuk, Loi Lam,Lo, Wai-Hung,Chan, Albert S. C.
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- Air-stable Ir-(P-Phos) complex for highly enantioselective hydrogenation of quinolines and their immobilization in poly(ethylene glycol) dimethyl ether (DMPEG)
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An air-stable catalyst system Ir-(P-Phos) catalyst was found to be highly effective in the asymmetric hydrogenation of quinoline derivatives. The catalyst immobilized in DMPEG was efficiently recovered and reused eight times, retaining reactivity and enan
- Xu, Lijin,Lam, Kim Hung,Ji, Jianxin,Wu, Jing,Fan, Qing-Hua,Lo, Wai-Hung,Chan, Albert S. C.
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- Novel Ir-SYNPHOS and Ir-DIFLUORPHOS catalysts for asymmetric hydrogenation of quinolines
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Novel Ir-SYNPHOS and Ir-DIFLUORPHOS catalysts were synthesized and used for the synthesis of tetrahydroquinolines via asymmetric hydrogenation of the corresponding quinoline derivatives. Georg Thieme Verlag Stuttgart.
- Deport, Coralie,Buchotte, Marie,Abecassis, Keren,Tadaoka, Hiroshi,Ayad, Tahar,Ohshima, Takashi,Genet, Jean-Pierre,Mashima, Kazushi,Ratovelomanana-Vidal, Virginie
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- Efficient enantioselective hydrogenation of quinolines catalyzed by conjugated microporous polymers with embedded chiral BINAP ligand
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Chiral Ir complexes were successfully used in the asymmetric hydrogenation of olefins, ketones, and quinolines. However, almost all the catalytic systems could not tolerate a high catalyst loading because of the formation of an irreversible iridium dimer and trimer during the reaction. It is expected that higher catalytic activity may be achieved if the Ir-complexes were isolated in space. The development of conjugated microporous polymers (CMPs) gives the opportunity for the spatial separation of the complexes. A series of chiral CMPs based on the chiral (R)-BINAP ligand (BINAP-CMPs) with different surface areas were synthesized. The BINAP ligands were separately distributed in the framework and were three times more active than the homogeneous catalyst (TOF 340 h-1 VS 100 h-1) for the asymmetric hydrogenation of quinolines.
- Wang, Xu,Li, Jun,Lu, Shengmei,Liu, Yan,Li, Can
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- Iridium-catalyzed asymmetric transfer hydrogenation of quinolines with Hantzsch esters
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The iridium-catalyzed enantioselective transfer hydrogenation of quinolines with Hantzsch esters was developed with up to 88% ee using [Ir(COD)Cl]2/(S)-SegPhos/I2 as a catalyst.
- Wang, Da-Wei,Zeng, Wei,Zhou, Yong-Gui
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- The development of double axially chiral phosphoric acids and their catalytic transfer hydrogenation of quinolines
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(Chemical Equation Presented) Building a better scaffold: Low loadings (0.2-1 mol%) of new double axially chiral phosphoric acid catalysts 1 based on bisbinol scaffold were used for asymmetric transfer hydrogenation. 2-Aryl- and 2-alkyl-substituted quinolines gave tetrahydroquinolines in excellent yields and with up to 98% ee and 2,3-disubstituted tetrahydroquinolines were prepared in high diastereo- and enantioselectivities (up to > 20:1 and 92% ee).
- Guo, Qun-Sheng,Du, Da-Ming,Xu, Jiaxi
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- Asymmetric hydrogenation of heteroaromatic compounds mediated by iridium-(P-OP) complexes
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A library of modular iridium complexes derived from P-OP ligands has been evaluated in iridium-mediated asymmetric hydrogenations of heteroaromatic compounds. The "lead" catalysts efficiently catalyzed the hydrogenation of several substituted quinolines and one quinoxaline (10 examples, up to 92% ee).
- Nunez-Rico, Jose L.,Fernandez-Perez, Hector,Benet-Buchholz,Vidal-Ferran, Anton
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- The use of phosphite-type ligands in the Ir-catalyzed asymmetric hydrogenation of heterocyclic compounds
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A series of chiral phosphite-type ligands was tested in asymmetric Ir-catalyzed hydrogenation of quinolines and 2,4,5,6-tetrahydro-1H-pyrazino(3,2, 1-j,k)carbazole. Hydrogenation of quinaldine hydrochloride provided superior enantioselectivity up to 65% ee compared to quinaldine free base. The ligands were tested for the first time in the asymmetric Ir-Ircatalyzed hydrogenation of 2,4,5,6-tetrahydro-1H-pyrazino(3,2,1-j,k)carbazole yielding the antidepressant drug, pirlindole. Chirality 26:56-60, 2013. 2013 Wiley Periodicals, Inc.
- Lyubimov, Sergey E.,Ozolin, Dmitry V.,Ivanov, Pavel Yu,Melman, Artem,Velezheva, Valeriya S.,Davankov, Vadim A.
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- Asymmetric hydrogenation of quinolines catalyzed by iridium with chiral ferrocenyloxazoline derived N,P ligands
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Chiral ferrocenyloxazoline derived N,P ligands are used in the iridium-catalyzed asymmetric hydrogenation of quinolines, and up to 92% ee was obtained. The role of the planar chirality is also studied.
- Lu, Sheng-Mei,Han, Xiu-Wen,Zhou, Yong-Gui
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- Kinetic resolution of (±)-2,3-dihydro-3-methyl-4H-1,4-benzoxazine, (±)-2-methyl-1,2,3,4-tetrahydroquinoline and (±)-2-methylindoline using N-tosyl-(S)-prolyl chloride
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Acylation of racemic 2,3-dihydro-3-methyl-4H-1,4-benzoxazine, 2-methyl-1,2,3,4-tetrahydroquinoline and 2-methylindoline with N-tosyl-(S)-prolyl chloride resulted in their kinetic resolution with the predominant formation of (R,S)-diastereoisomeric amides,
- Krasnov, Victor P.,Levit, Galina L.,Bukrina, Iraida M.,Andreeva, Irina N.,Sadretdinova, Liliya Sh.,Korolyova, Marina A.,Kodess, Mikhail I.,Charushin, Valery N.,Chupakhin, Oleg N.
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- Inhibiting deactivation of iridium catalysts with bulky substituents on coordination atoms
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Introducing bulky groups on the coordination phosphorus atoms can effectively block the formation of inactive dimer species and improve the activity of the iridium catalysts. Results of ESI-MS analysis gave strong evidence. This strategy was successfully
- Wang, Duo-Sheng,Zhou, Juan,Wang, Da-Wei,Guo, Yin-Long,Zhou, Yong-Gui
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- Asymmetric hydrogenation of quinolines catalyzed by iridium complexes of monodentate BINOL-derived phosphoramidites
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The monodentate BINOL-derived phosphoramidite PipPhos is used as ligand for the iridium-catalyzed asymmetric hydrogenation of 2- and 2,6-substituted quinolines. If tri-ortho-tolylphosphine and/or chloride salts are used as additives enantioselectivities are strongly enhanced up to 89%. NMR indicates that no mixed complexes are formed upon addition of tri-ortho-tolylphosphine.
- Mrsic, Natasa,Lefort, Laurent,Boogers, Jeroen A. F.,Minnaard, Adriaan J.,Feringa, Ben L.,De Vries, Johannes G.
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- Enantioselective hydrogenation of quinolines catalyzed by Ir(BINAP)-cored dendrimers: Dramatic enhancement of catalytic activity
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Figure presented The asymmetric hydrogenation of quinolines catalyzed by chiral dendritic catalysts derived from BINAP gave the corresponding products with high enantioselectivities (up to 93%), excellent catalytic activities (TOF up to 3450 h-1), and productivities (TON up to 43 000). In addition, the third-generation catalyst could be recovered by precipitation and filtration and reused at least six times with similar enantioselectivity.
- Wang, Zhi-Jian,Deng, Guo-Jun,Li, Yong,He, Yan-Mei,Tang, Wei-Jun,Fan, Qing-Hua
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- Application of phosphine-phosphite ligands in the iridium catalyzed enantioselective hydrogenation of 2-Methylquinoline
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The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the natureof the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, has improved the enantioselectivity of the reaction up to 73% ee. The influence of additives in this reaction has also been investigated. Contrary to the beneficial influence observed in related catalytic systems, iodine has a deleterious effect in the present case. Otherwise, aryl phosphoric acids produce a positive impact on catalyst activity without a decrease on enantioselectivity.
- Rubio, Miguel,Pizzano, Antonio
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- Synthesis of new amidophosphite ligand and its application in Ir-catalyzed asymmetric hydrogenation of heterocyclic compounds
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A new chiral amidophosphite ligand was synthesized and tested in the iridium-catalyzed hydrogenation of heterocyclic compounds. The enantioselectivity of hydrogenation of 2-methyl- quinoline considerably increases when piperidine hydrochloride is used as an additive. The hydrogenation reaction of 8-methyl-2,4,5,6-tetrahydro-1H-pyrazino[3,2,1-jk] carbazole by metal complex was conducted for the first time to prepare enantiomerically enriched anti- depressant Pyrazidol.
- Lyubimov,Ozolin,Pavlov,Fedorova,Velezheva,Davankov
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- Asymmetric hydrogenation of quinolines with recyclable and air-stable iridium catalyst systems
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The iridium complex-catalyzed asymmetric hydrogenation of quinolines in a DMPEG/hexane biphasic system was studied. Catalysts with C2-symmetric ligands such as Xyl-P-Phos, Cl-MeO-BIPHEP, SYNPHOS, and DifluorPhos are highly effective for this type of reaction. Most of the catalysts tested can be retained in DMPEG (Mn = 500), and the asymmetric hydrogenation of various quinoline substrates can be carried out in DMPEG/hexane biphasic system with up to 92% ee. The catalysts and the products can be separated via simple phase separation, and the reactivity/stereoselectivity of the catalysts can be retained for at least three reaction cycles.
- Chan, Sau Hing,Lam, Kim Hung,Li, Yue-Ming,Xu, Lijin,Tang, Weijun,Lam, Fuk Loi,Lo, Wai Hung,Yu, Wing Yiu,Fan, Qinghua,Chan, Albert S.C.
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- RUTHENIUM CATALYZED REDUCTION OF NITROARENES AND AZAAROMATIC COMPOUNDS USING FORMIC ACID.
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Various nitroarenes having chloro, ethyl, or methoxy substituents were reduced to the corresponding aminoarenes in high yields using formic acid in the presence of a catalytic amount of RuCl//2(PPh//3)//3. For example, 4-chloronitrobenzene was converted in 99% conversion with 98% selectivity at 125 degree C for 5 hr. 4-Nitroacetophenone was reduced chemoselectively to 1-(4-nitrophenyl)ethanol in 74% isolated yield under the same reaction conditions. Formic acid could also be employed as reductant for hydrogenation of heterocyclic compounds such as quinoline, indole, and quinoxaline in the presence of the ruthenium catalyst. 2-Methylquinoline was hydrogenated to 1,2,3,4-tetrahydro-2-methylquinoline in 93% conversion with 100% selectivity.
- Watanabe,Ohta,Tsuji,Hiyoshi,Tsuji
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- Solvent-Regulated Asymmetric Hydrogenation of Quinoline Derivatives in Oligo(Ethylene Glycol)s through Host–Guest Interactions
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The asymmetric hydrogenation of quinolines in oligo(ethylene glycol)s (OEGs) and poly(ethylene glycol)s (PEGs) with chiral cationic ruthenium diamine complexes has been investigated. Interestingly, in liquid PEGs or long-chain OEGs, the Ru catalysts lost their reactivity. Upon the addition of a little MeOH, the hydrogenation of quinoline was switched “ON”. Evidence from mass spectrometry and control experiments revealed that encapsulation of the quinolinium salt by PEG or long-chain OEG molecules through supramolecular interactions is possibly the main reason for such a switchable hydrogenation reaction. Moreover, the asymmetric hydrogenation of 2-substituted quinoline derivatives was achieved in triethylene glycol (3-OEG), thereby affording 1,2,3,4-tetrahydroquinolines with excellent reactivities and enantioselectivities (up to 99 % ee). Furthermore, the Ru catalyst could be readily recycled for both pure 3-OEG and biphasic 3-OEG/n-hexane systems without a clear loss of reactivity and enantioselectivity.
- Wang, Tianli,Chen, Ya,Ouyang, Guanghui,He, Yan-Mei,Li, Zhiyan,Fan, Qing-Hua
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- Asymmetric hydrogenation of quinolines catalyzed by iridium complexes of BINOL-derived diphosphonites
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A chiral diphosphonite, derived from BINOL and with an achiral diphenyl ether backbone, is an excellent ligand for the Ir-catalyzed asymmetric hydrogenation of quinolines; achiral P-ligands serving as possible additives (ee = 73-96%). The Royal Society of Chemistry 2006.
- Reetz, Manfred T.,Li, Xiaoguang
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- Asymmetric hydrogenation of quinolines with high substrate/catalyst ratio
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The chiral diphosphinite ligand derived from (R)-1,1′-spirobiindane- 7,7′-diol has been found to be highly effective in the Ir-catalyzed asymmetric hydrogenation of quinolines with high substrate/catalyst ratio (up to 5000) and high enantioselectivity (up to 94% ee). The Royal Society of Chemistry.
- Tang, Wei-Jun,Zhu, Shou-Fei,Xu, Li-Jin,Zhou, Qi-Lin,Fan, Qing-Hua,Zhou, Hai-Feng,Lam, Kimhung,Chan, Albert S. C.
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- Kinetic resolution of (±)-2-methyl-1,2,3,4-tetrahydroquinoline and (±)-2-methylindoline
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The acylation of racemic 2-methyl-1,2,3,4-tetrahydroquinoline and 2-methylindoline by (S)-naproxen acyl chloride resulted in their kinetic resolution with the predominant formation of (S,S)-diastereoisomeric amides (de 78-76%), recrystallisation of which followed by acid hydrolysis gave individual (S)-isomers of heterocyclic amines.
- Krasnov, Victor P.,Levit, Galina L.,Andreeva, Irina N.,Grishakov, Alexander N.,Charushin, Valery N.,Chupakhin, Oleg N.
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- Highly enantioselective iridium-catalyzed hydrogenation of heteroaromatic compounds, quinolines
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The highly enantioselective hydrogenation of quinoline derivatives is developed using [Ir(COD)Cl]2/(R)-MeO-Biphep/I2 system, and this methodology has been applied to the asymmetric synthesis of three naturally occurring alkaloids angustureine, galipinine, and cuspareine. This method provided an efficient access to a variety of optically active tetrahydroquinolines with up to 96% ee. Copyright
- Wang, Wen-Bo,Lu, Sheng-Mei,Yang, Peng-Yu,Han, Xiu-Wen,Zhou, Yong-Gui
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- Synthesis of tunable bisphosphine ligands and their application in asymmetric hydrogenation of quinolines
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(Chemical Equation Presented) A series of tunable axial chiral bisphosphine ligands have been synthesized from (S)-MeO-Biphep. The Ir complex of the MeO-PEG-supported ligand (S)-4k has been successfully applied in asymmetric hydrogenation of quinolines with up to 92% ee. The catalyst system is air-stable and recyclable.
- Wang, Xiao-Bing,Zhou, Yong-Gui
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- Efficient asymmetric hydrogenation of quinolines in neat water catalyzed by chiral cationic Ru-diamine complexes
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We describe herein highly effective asymmetric hydrogenation of quinolines in undegassed water catalyzed by chiral cationic Ru-diamine complexes for the first time. This facile and green protocol is applicable to the scaled-up synthesis of 6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline, a key intermediate for the preparation of the antibacterial agent (S)-flumequine, with 98% ee. the Partner Organisations 2014.
- Yang, Zhusheng,Chen, Fei,He, Yan-Mei,Yang, Nianfa,Fan, Qing-Hua
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- Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N-Ferrocenyl NHC-Iridium Complex
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Annulated planar chiral N-ferrocenylimidazolones, obtained by acid-mediated cyclization of diphenylmethanol derivatives, may be reduced with diisobutylaluminium hydide (DIBAL-H) to afford a series of surprisingly stable and isolable hemiaminal ether aminals. Two of these derivatives can be oxidized with triphenylcarbenium tetrafluoroborate to imidazolinium salt precursors of N-heterocyclic carbenes (NHCs). Deprotonation of these salts in the presence of (cyclooctadiene)iridium chloride dimer {[Ir(COD)Cl]2} provides chiral coordination complexes bearing N-ferrocenyl NHCs with unique rigid tetracyclic frameworks. Cationic analogues of these complexes catalyze the asymmetric hydrogenation of 2-substituted quinolines under very mild conditions (1 mol% complex, 1 mol% PPh3, 1-5 atm H2, toluene, 25 C) in appreciable enantioselectivity (up to 90:10 er). The sensitivity of the hydrogenation process to changes in the phosphine additive suggests that an outer-sphere reaction mechanism may be involved, as proposed for a related achiral NHC-Ir complex reported by Crabtree and co-workers.
- John, Joshni,Wilson-Konderka, Cody,Metallinos, Costa
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- Oxygen-implanted MoS2 nanosheets promoting quinoline synthesis from nitroarenes and aliphatic alcohols via an integrated oxidation transfer hydrogenation-cyclization mechanism
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We herein report that MoS2 with oxygen-implanting modification (O-MoS2) can work as a multifunctional catalyst to achieve the one-pot quinoline synthesis from basic nitroarenes and aliphatic alcohols. Different from common knowledge that the application of MoS2-based catalysts and above quinoline synthesis need anaerobic conditions, we conduct the heterogeneous catalysis under an unusual air atmosphere. Catalyst characterization and experimental results indicate that the MoOx clusters implanted in the MoS2 skeleton, not the coordinatively unsaturated Mo sites (CUS Mo), dominate the generation of quinolines. By overturning the catalysis perception that O2 adsorption on MoSx can deactivate the MoS2-based catalysts using an efficient method for in situ healing of the MoOx structure in O-MoS2 and protecting the O-MoS2 catalyst by inhibiting unwanted MoOx elimination with extra H*, we innovatively introduce O2 into the quinoline synthesis. The robust O-MoS2 can be consecutively used ten times without regeneration and it offers 69-75% yields of 2-methylquinoline from nitrobenzene and ethanol. Furthermore, different from the traditional transfer hydrogenation-condensation mechanism, an integrated oxidation-transfer hydrogenation-cyclization mechanism is proposed over the O-MoS2 catalyst.
- Gao, Zhuyan,Huang, Zhipeng,Lu, Jianmin,Mu, Junju,Ren, Puning,Su, Kaiyi,Wang, Feng,Zhang, Chaofeng,Zhang, Shichao
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supporting information
p. 1704 - 1713
(2022/03/08)
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- Method for selective catalytic hydrogenation of aromatic heterocyclic compounds in non-hydrogen participation manner
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The invention discloses a method for selective catalytic hydrogenation of aromatic heterocyclic compounds in a non-hydrogen participation manner. The method comprises the following steps: by taking 1, 5-cyclooctadiene iridium chloride dimer as a catalyst and phenylsilane as a hydrogen source, carrying out stirring reaction under mild conditions without adding a ligand, namely catalytically hydrogenating the aromatic heterocyclic compounds to obtain hydrogenated products of the aromatic heterocyclic compounds. The method has the advantages of low cost, mild reaction conditions, high selectivity and the like, and special equipment such as a high-pressure kettle and the like and high-temperature conditions which are required when hydrogen is used are avoided.
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Paragraph 0025-0029; 0055-0069
(2021/08/19)
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- Pd/c catalyzed decarboxylation-transfer hydrogenation of quinoline carboxylic acids
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Pd/C catalyzed decarboxylation-transfer hydrogenation of quinoline carboxylic acids and transfer hydrogenation of quinolines had been developed for the synthesis of 1,2,3,4-tetrahydroquinolines. These two processes were implemented smoothly using Pd/C (0.9 mol%) as a catalyst with ammonium formate as a hydrogen source in ethanol at 80oC. The reaction system can also be applied to transfer hydrogenation of benzo[h]quinoline and 2,9-dimethyl-1,10-phenanthroline with good to excellent yields. And the gram scale and recycling of catalyst had been tested with good results. Furthermore, the mechanism of Pd/C catalyzed reduction of quino-line carboxylic acids and quinolines had been proposed.
- Zhou, Xiao-Yu,Chen, Xia
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p. 625 - 633
(2021/09/30)
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- Catalytic Hydrogenation of Substituted Quinolines on Co–Graphene Composites
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A set of 20 composites was prepared by pyrolysis of Co2+ complexes with 1,10-phenanthroline, melamine and 1,2-diaminobenzene. These composites were tested as the catalysts for the hydrogenation of quinolines. As shown by powder X-ray diffraction and TEM, the composited contained Co particles of several dozen nm sizes. The composition (elements content), Raman spectra X-ray photoelectron spectra parameters of the composites were analyzed. It was found that there was no distinct factor that controlled the yield of 1,2,3,4-tetrahydroquinolines in the investigated process. The yields of the respective products were in the range 90–100 %. The three most active composites were selected for scale-up and hydrogenation of a series of substituted quinolines. Up to 97 % yield of 1,2,3,4-tetrahydroquinoline was obtained on a 50 g scale. Five representative substituted quinolines were synthesized on a 10–20 grams scale using the Co-containing composites as the catalysts.
- Asaula, Vitalii M.,Buryanov, Volodymyr V.,Solod, Bohdan Y.,Tryus, Daryna M.,Pariiska, Olena O.,Kotenko, Igor E.,Volovenko, Yulian M.,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Kolotilov, Sergey V.
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p. 6616 - 6625
(2021/12/24)
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- Method for preparing tetrahydroquinoline compounds by catalytic hydrogenation of ruthenium catalyst
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The invention relates to a method for preparing tetrahydroquinoline compounds by catalytic hydrogenation of a ruthenium catalyst, which comprises the following steps: by using p-cymene ruthenium chloride dimer as a catalyst and hydrogen as a reducing agent, mixing the p-cymene ruthenium chloride dimer, phosphine ligand and quinoline compounds, and dissolving the mixture in an organic solvent to react, and carrying out post-treatment to obtain the tetrahydroquinoline derivative. Compared with the prior art, the method has the advantages of easily available raw materials, mild conditions, simpleoperation, atom economy, simple and green synthesis process, mild reaction conditions, excellent selectivity, high yield and good reaction universality, and has a wide application value in fine chemical intermediate synthesis.
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Paragraph 0030-0033
(2021/01/29)
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- Heterogeneous Hydrogenation of Quinoline Derivatives Effected by a Granular Cobalt Catalyst
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We communicate a convenient method for the pressure hydrogenation of quinolines in aqueous solution by using a particulate cobalt-based catalyst that is prepared in situ from simple Co(OAc)2 4H2O through reduction with abundant zinc powder. This catalytic protocol permits a brisk and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines thereby relying solely on easy-to-handle reagents that are all readily obtained from commercial sources. Both the reaction setup assembly and the autoclave charging procedure are conducted on the bench outside an inert-gas-operated containment system, thus rendering the overall synthesis time-saving and operationally very simple.
- Timelthaler, Daniel,Topf, Christoph
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p. 629 - 642
(2021/11/22)
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- Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
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Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
- Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
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p. 4724 - 4728
(2021/09/06)
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- Homogeneous pressure hydrogenation of quinolines effected by a bench-stable tungsten-based pre-catalyst
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We report on an operationally simple catalytic method for the tungsten-catalyzed hydrogenation of quinolines through the use of the easily handled and self-contained precursor [WCl(η5-Cp)(CO)3]. This half sandwich complex is indefinitely storable on the bench in simple screw-capped bottles or stoppered flasks and can, if required, be prepared on a multi-gram scale while the actual catalytic transformations were performed in the presence of a Lewis acid in order to achieve both decent substrate conversions and product yields. The described method represents a facile and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines that circumvents the use of cost-intensive and oxygen-sensitive phosphine ligands as well as auxiliary hydride reagents.
- Heizinger, Christian,Topf, Christoph,Vielhaber, Thomas
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p. 451 - 461
(2021/11/11)
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- Low-Temperature Nickel-Catalyzed C?N Cross-Coupling via Kinetic Resolution Enabled by a Bulky and Flexible Chiral N-Heterocyclic Carbene Ligand
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The transition-metal-catalyzed C?N cross-coupling has revolutionized the construction of amines. Despite the innovations of multiple generations of ligands to modulate the reactivity of the metal center, ligands for the low-temperature enantioselective amination of aryl halides remain a coveted target of catalyst engineering. Designs that promote one elementary reaction often create bottlenecks at other steps. We here report an unprecedented low-temperature (as low as ?50 °C), enantioselective Ni-catalyzed C?N cross-coupling of aryl chlorides with sterically hindered secondary amines via a kinetic resolution process (s factor up to >300). A bulky yet flexible chiral N-heterocyclic carbene (NHC) ligand is leveraged to drive both oxidative addition and reductive elimination with low barriers and control the enantioselectivity. Computational studies indicate that the rotations of multiple σ-bonds on the C2-symmetric chiral ligand adapt to the changing needs of catalytic processes. We expect this design would be widely applicable to diverse transition states to achieve other challenging metal-catalyzed asymmetric cross-coupling reactions.
- Hong, Xin,Shi, Shi-Liang,Wang, Zi-Chao,Xie, Pei-Pei,Xu, Youjun
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supporting information
p. 16077 - 16084
(2021/06/17)
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- Development of efficient solid chiral catalysts with designable linkage for asymmetric transfer hydrogenation of quinoline derivatives
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This vertically self-pillared (VSP) structure extends the application range of traditional porous materials with facile mass/ion transport and enhanced reaction kinetics. Here, we prepare a single crystal metal-organic framework (MOF), employing the ZIF-67 structure as a proof of concept, which is constructed by vertically self-pillared nanosheets (VSP-MOF). We further converted VSP-MOF into VSP-cobalt sulfide (VSP-CoS2) through a sulfidation process. Catalysis plays an important role in almost all battery technologies; for metallic batteries, lithium anodes exhibit a high theoretical specific capacity, low density, and low redox potential. However, during the half-cell reaction (Li++e=Li), uncontrolled dendritic Li penetrates the separator and solid electrolyte interphase layer. When employed as a composite scaffold for lithium metal deposition, there are many advantage to using this framework: 1) the VSP-CoS2 substrate provides a high specific surface area to dissipate the ion flux and mass transfer and acts as a pre-catalyst, 2) the catalytic Co center favors the charge transfer process and preferentially binds the Li+ with the enhanced electrical fields, and 3) the VSP structure guides the metallic propagation along the nanosheet 2D orientation without the protrusive dendrites. All these features enable the VSP structure in metallic batteries with encouraging performances.
- Ren, Yiqi,Tao, Lin,Li, Chunzhi,Jayakumar, Sanjeevi,Li, He,Yang, Qihua
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p. 1576 - 1585
(2021/05/10)
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- Alternative Strategy to Obtain Artificial Imine Reductase by Exploiting Vancomycin/D-Ala-D-Ala Interactions with an Iridium Metal Complex
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Based on the supramolecular interaction between vancomycin (Van), an antibiotic glycopeptide, and D-Ala-D-Ala (DADA) dipeptides, a novel class of artificial metalloenzymes was synthesized and characterized. The presence of an iridium(III) ligand at the N-terminus of DADA allowed the use of the metalloenzyme as a catalyst in the asymmetric transfer hydrogenation of cyclic imines. In particular, the type of link between DADA and the metal-chelating moiety was found to be fundamental for inducing asymmetry in the reaction outcome, as highlighted by both computational studies and catalytic results. Using the [IrCp*(m-I)Cl]Cl Van complex in 0.1 M CH3COONa buffer at pH 5, a significant 70% (S) e.e. was obtained in the reduction of quinaldine B.
- Facchetti, Giorgio,Bucci, Raffaella,Fusè, Marco,Erba, Emanuela,Gandolfi, Raffaella,Pellegrino, Sara,Rimoldi, Isabella
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p. 2976 - 2982
(2021/03/01)
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- Manganese-Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by π–π Interaction**
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The non-noble metal-catalyzed asymmetric hydrogenation of N-heteroaromatics, quinolines, is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of quinolines, affording high yields and enantioselectivities (up to 97 % ee). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which is competitive with the activity of most effective noble metal catalysts for this reaction. The precise regulation of the enantioselectivity were ensured by a π–π interaction.
- Liu, Chenguang,Wang, Mingyang,Liu, Shihan,Wang, Yujie,Peng, Yong,Lan, Yu,Liu, Qiang
-
supporting information
p. 5108 - 5113
(2021/01/21)
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- Enantiodivergent Synthesis of Chiral Tetrahydroquinoline Derivatives via Ir-Catalyzed Asymmetric Hydrogenation: Solvent-Dependent Enantioselective Control and Mechanistic Investigations
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Ir-catalyzed asymmetric hydrogenation of quinolines was developed, and both enantiomers of chiral tetrahydroquinoline derivatives could be easily obtained, respectively, in high yields with good enantioselectivities through the adjustment of reaction solvents (toluene/dioxane: up to 99% yield, 98% ee (R), TON = 680; EtOH: up to 99% yield, 94% ee (S), TON = 1680). It provided an efficient and simple synthetic strategy for the enantiodivergent synthesis of chiral tetrahydroquinolines, and gram-scale asymmetric hydrogenation proceeded well with low-catalyst loading in these two reaction systems. A series of deuterium-labeling experiments, control experiments, and 1H NMR and electrospray ionization-mass spectrometry experiments have been conducted, and a reasonable and possible reaction process was revealed on the basis of these useful observations.
- Han, Zhengyu,Liu, Gang,Yang, Xuanliang,Dong, Xiu-Qin,Zhang, Xumu
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p. 7281 - 7291
(2021/06/30)
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- Organometallic Synthesis of Bimetallic Cobalt-Rhodium Nanoparticles in Supported Ionic Liquid Phases (CoxRh100?x@SILP) as Catalysts for the Selective Hydrogenation of Multifunctional Aromatic Substrates
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The synthesis, characterization, and catalytic properties of bimetallic cobalt-rhodium nanoparticles of defined Co:Rh ratios immobilized in an imidazolium-based supported ionic liquid phase (CoxRh100?x@SILP) are described. Following an organometallic approach, precise control of the Co:Rh ratios is accomplished. Electron microscopy and X-ray absorption spectroscopy confirm the formation of small, well-dispersed, and homogeneously alloyed zero-valent bimetallic nanoparticles in all investigated materials. Benzylideneacetone and various bicyclic heteroaromatics are used as chemical probes to investigate the hydrogenation performances of the CoxRh100?x@SILP materials. The Co:Rh ratio of the nanoparticles is found to have a critical influence on observed activity and selectivity, with clear synergistic effects arising from the combination of the noble metal and its 3d congener. In particular, the ability of CoxRh100?x@SILP catalysts to hydrogenate 6-membered aromatic rings is found to experience a remarkable sharp switch in a narrow composition range between Co25Rh75 (full ring hydrogenation) and Co30Rh70 (no ring hydrogenation).
- Rengshausen, Simon,Van Stappen, Casey,Levin, Natalia,Tricard, Simon,Luska, Kylie L.,DeBeer, Serena,Chaudret, Bruno,Bordet, Alexis,Leitner, Walter
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- Highly efficient one-pot multi-directional selective hydrogenation and N-alkylation catalyzed by Ru/LDH under mild conditions
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Atomic economy, non-toxicity, harmlessness and multidirectional selectivity advocated by green chemistry have increasingly become a hot and difficult research topic. Herein, we present a highly efficient, one-pot tandem and easy-to-operate method through which we could directly produce a broad range of multi-directional selective hydrogenated amines or N-alkyl aliphatic amines using aromatic nitro compounds as raw materials. Ru/LDH with characteristics of layered mesoporous structure, well dispersed small Ru nanoparticles and LDH stabilization to the Ru NPs was employed as the catalyst. It is remarkable that multi-directional superb chemoselectivity to aromatic amines, alicyclic amines as well as N-alkyl aliphatic amines could be achieved with excellent catalytic activity and recyclability by tuning reaction conditions over 5wt%Ru/LDH-2. Additionally, this catalytic system also exhibited attractive activity and multi-directional chemoselectivity in the hydrogenation of quinoline and its derivatives with solvents of different polarity. Chemoselectivity to 5,6,7,8-tetrahydroquinoline derivatives could reach as high as 95.6 %.
- Zhang, Sishi,Xu, Jie,Cheng, Hongmei,Zang, Cuicui,Sun, Bin,Jiang, Heyan,Bian, Fengxia
-
supporting information
(2020/03/30)
-
- BORON COMPOUND, AND MANUFACTURING METHOD OF HYDROGENATED ARTICLE, POLYMER AND ADDITION BODY USING THE SAME
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PROBLEM TO BE SOLVED: To provide a novel boron compound capable of being used as a catalyst or the like for suppressing catalysts poisoning by a hydrogenation reaction even under a condition that carbon monoxide and/or carbon dioxide coexist at high conce
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-
Paragraph 0066-0076
(2020/04/01)
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- Boric acid catalyzed chemoselective reduction of quinolines
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Boric acid promoted transfer hydrogenation of substituted quinolines to synthetically versatile 1,2,3,4-tetrahydroquinolines (1,2,3,4-THQs) was described under mild reaction conditions using a Hantzsch ester as a mild organic hydrogen source. This methodology is practical and efficient, where isolated yields are excellent and reducible functional groups are well tolerated in the N-heteroarene moiety. The reaction parameters and tentative mechanistic pathways are demonstrated by various control experiments and NMR studies. The present work can also be scaled up to obtain gram quantities and the utility of the developed process is illustrated by the transformation of 1,2,3,4-THQs into a series of biologically important molecules including the antiarrhythmic drug nicainoprol.
- Adhikari, Priyanka,Bhattacharyya, Dipanjan,Das, Animesh,Konwar, Monuranjan,Nandi, Sekhar,Sarmah, Bikash Kumar
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supporting information
p. 1214 - 1220
(2020/02/22)
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- Ir-Catalyzed Reversible Acceptorless Dehydrogenation/Hydrogenation of N-Substituted and Unsubstituted Heterocycles Enabled by a Polymer-Cross-Linking Bisphosphine
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The polystyrene-cross-linking bisphosphine ligand PS-DPPBz was effective for the Ir-catalyzed reversible acceptorless dehydrogenation/hydrogenation of N-heterocycles. Notably, this protocol is applicable to the dehydrogenation of N-substituted indoline derivatives with various N-substituents with different electronic and steric natures. A reaction pathway involving oxidative addition of an N-adjacent C(sp3)-H bond to a bisphosphine-coordinated Ir(I) center is proposed for the dehydrogenation of N-substituted substrates.
- Zhang, Deliang,Iwai, Tomohiro,Sawamura, Masaya
-
supporting information
p. 5240 - 5245
(2020/07/03)
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- A proton-responsive annulated mesoionic carbene (MIC) scaffold on IR complex for proton/hydride shuttle: An experimental and computational investigation on reductive amination of aldehyde
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A Cp*Ir(III) complex (1) bearing a proton-responsive hydroxy unit on an annulated imidazo[1,2-a][1,8]naphthyridine based mesoionic carbene scaffold was synthesized by two different synthetic routes. The molecular structure of 1 revealed an anionic lactam form of the ligand. The acid?base equilibrium between the lactam-lactim tautomers on the ligand scaffold was examined by 1H NMR and UV?vis spectra. The pKa of the appendage ?OH group in the lactim form of 1 was estimated to assess the proton transfer property of the catalyst. The catalytic efficacy of 1 for reductive amination of aldehyde was evaluated by utilizing three different hydrogen sources: molecular H2iPrOH/KOtBu combination, and HCOOH/Et3N (5:2) azeotropic mixture. The HCOOH/Et3N (5:2) azeotropic mixture rotocol was found to be the best amon the three different h dro enation methods. Catalyst 1 hydrogenates imines chemoselectively over carbonyls under the reaction conditions. A range of aldehydes was reductively aminated to the corresponding secondary amines using the HCOOH/Et3N (5:2) azeotropic mixture. Further, catalyst 1 showed high efficiency for the reduction of a wide variety of N-heterocyclic imine derivatives. The lactam-lactim tautomerization of the ligand system is proposed for direct hydrogenation, whereas only the lactam form operates in the strongly basic medium (iPrOH/KOtBu). Under HCOOH/Et3N (5:2) conditions, the lactam scaffold is not protonated; rather, an outer-sphere hydride transfer from formate to the Ir is proposed, which is supported by 1H NMR and DFT calculations. Finally, ligand-promoted hydride transfer from metal-hydride to the protonated imine affords the corresponding amine. A close agreement between the experimentally estimated and computed thermodynamic/kinetic parameters gives credence to the metal-ligand cooperative mechanism for the imine hydrogenation reaction using the HCOOH/Et3N (5:2) azeotropic mixture.
- Bera, Jitendra K.,Daw, Prosenjit,Din Reshi, Noor U.,Ehmann, Kira R.,H?lscher, Markus,Leitner, Walter,Pandey, Pragati
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p. 3849 - 3863
(2020/11/23)
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- A General Catalyst Based on Cobalt Core–Shell Nanoparticles for the Hydrogenation of N-Heteroarenes Including Pyridines
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Herein, we report the synthesis of specific silica-supported Co/Co3O4 core–shell based nanoparticles prepared by template synthesis of cobalt-pyromellitic acid on silica and subsequent pyrolysis. The optimal catalyst material allows for general and selective hydrogenation of pyridines, quinolines, and other heteroarenes including acridine, phenanthroline, naphthyridine, quinoxaline, imidazo[1,2-a]pyridine, and indole under comparably mild reaction conditions. In addition, recycling of these Co nanoparticles and their ability for dehydrogenation catalysis are showcased.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Kreyenschulte, Carsten,Murugesan, Kathiravan
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supporting information
p. 17408 - 17412
(2020/08/21)
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- Simple manganese carbonyl catalyzed hydrogenation of quinolines and imines
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Manganese-catalyzed hydrogenation of unsaturated molecules has made tremendous progresses recently benefiting from non-innocent pincer or bidentate ligands for manganese. Herein, we describe the hydrogenation of quinolines and imines catalyzed by simple manganese carbonyls, Mn2(CO)10 or MnBr(CO)5, thus eliminating the prerequisite pincer-type or bidentate ligands.
- Wang, Zelong,Chen, Lei,Mao, Guoliang,Wang, Congyang
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p. 1890 - 1894
(2020/03/04)
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- Convenient synthesis of cobalt nanoparticles for the hydrogenation of quinolines in water
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Easily accessible cobalt nanoparticles are prepared by hydrolysis of NaBH4 in the presence of inexpensive Co(ii) salts. The resulting material is an efficient catalyst for the hydrogenation of quinoline derivatives in water. The activity and chemoselectivity of this catalyst are comparable to other cobalt-based heterogeneous catalysts.
- Beller, Matthias,Dorcet, Vincent,Fischmeister, Cedric,Hervochon, Julien,Junge, Kathrin
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p. 4820 - 4826
(2020/08/14)
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- Fast and Efficient Nickel(II)-catalysed Transfer Hydrogenation of Quinolines with Ammonia Borane
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Herein we report the first Ni(II)-catalysed transfer hydrogenation of quinolines using ammonia borane (AB) as hydrogen (H2) source. An in situ generated Ni(II)-bis(pyrazolyl)pyridine pre-catalyst could hydrogenate quinoline and its derivatives in excellent yields of up to 90% at 25 °C in 30 minutes. Spectroscopic studies revealed that a Ni(II)-hydride is responsible for the transfer hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline via a 1,4-dihydroquinoline intermediate. (Figure presented.).
- Vermaak, Vincent,Vosloo, Hermanus C. M.,Swarts, Andrew J.
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supporting information
p. 5788 - 5793
(2020/12/01)
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- Enantioselective Synthesis of Tetrahydroquinolines via One-Pot Cascade Biomimetic Reduction?
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A novel and efficient protocol for the synthesis of chiral tetrahydroquinoline derivatives with excellent enantioselectivities and high yields has been developed through one-pot cascade biomimetic reduction. The detailed reaction pathway includes the acid-catalyzed and ruthenium-catalyzed formation of aromatic quinoline intermediates and biomimetic asymmetric reduction.
- Zhao, Zi-Biao,Li, Xiang,Chen, Mu-Wang,Wu, Bo,Zhou, Yong-Gui
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supporting information
p. 1691 - 1695
(2020/11/03)
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- Exploration of chiral diastereomeric spiroketal (SPIROL)-based phosphinite ligands in asymmetric hydrogenation of heterocycles
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New and readily available chiral SPIROL-based diphosphinite ligands (SPIRAPO) have been prepared and employed for iridium-catalyzed asymmetric hydrogenations of quinolines, quinoxalines and 2H-1,4-bezoxazin-2-ones. While the structurally similar (R,R,R)-SPIRAPO and (R)-SPINOL-based phosphinites were not the best ligands for these transformations, the (S,R,R)-diastereomer of SPIRAPO was found to be highly effective ligand for the reduction of 20 different heterocyclic systems with loadings as low as S/C = 10?000. This dearomatizative hydrogenation provided direct access to optically active tetrahydroquinolines in high enantioselectivities (up to 94percent ee) and excellent yields (up to 99percent), and was used to generate 1.75 g of natural alkaloid (-)-(R)-angustureine. This protocol was subsequently extended to achieve asymmetric hydrogenation of quinoxalines and 2H-1,4-benzoxazin-2-ones in good to excellent enantioselectivities.
- Sun, Siyuan,Nagorny, Pavel
-
supporting information
p. 8432 - 8435
(2020/08/13)
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- Efficient Asymmetric Hydrogenation of Quinolines over Chiral Porous Polymers Integrated with Substrate Activation Sites
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Heterogeneous asymmetric hydrogenation of quinolines for the production of optically active tetrahydroquinoline derivatives still remains a difficult task due to the aromatic stability of quinolines. Herein, we reported efficient heterogeneous asymmetric hydrogenation of quinolines over chiral porous polymers integrated with both chiral active sites (VDPEN-RuOTs) and substrate activation sites (TsOH). The porous polymer integrated with TsOH is 10 times more active than that without TsOH in the asymmetric hydrogenation of 2-methylquinoline. The volcano curve of TOF with the TsOH/Ru ratio confirms the synergistic catalysis of VDPEN-RuOTs and TsOH. Comparison results with a homogeneous catalytic system imply that the synergy between chiral centers and acidic sites is greatly enhanced in the polymer network. Under optimized conditions, the chiral porous polymer afforded up to 90% ee with 90 h-1 TOF, which is one of the best solid catalysts for asymmetric hydrogenation of quinoline derivatives ever reported. Furthermore, the bifunctional porous polymers realized the asymmetric cascade hydrogenation/reductive amination reaction to obtain benzo-quinolizidines. Our primary results suggest that the incorporation of substrate activation sites near chiral centers is an efficient strategy for the synthesis of high-performance solid catalysts for heterogeneous asymmetric catalysis.
- Chen, Xuelian,Li, Chunzhi,Li, He,Liu, Lina,Ren, Yiqi,Tao, Lin,Yang, Qihua
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p. 1783 - 1791
(2020/01/31)
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- Synthesis of Tetrahydroquinolines via Borrowing Hydrogen Methodology Using a Manganese PN3Pincer Catalyst
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A straightforward and selective synthesis of 1,2,3,4-tetrahydroquinolines starting from 2-aminobenzyl alcohols and simple secondary alcohols is reported. This one-pot cascade reaction is based on the borrowing hydrogen methodology promoted by a manganese(I) PN3 pincer complex. The reaction selectively leads to 1,2,3,4-tetrahydroquinolines thanks to a targeted choice of base. This strategy provides an atom-efficient pathway with water as the only byproduct. In addition, no further reducing agents are required.
- Hofmann, Natalie,Homberg, Leonard,Hultzsch, Kai C.
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supporting information
p. 7964 - 7970
(2020/11/02)
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- Ortho-alkylated electron-rich arylamine, and preparation method and application thereof
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The invention belongs to the technical field of organic synthesis, and particularly relates to an ortho-alkylated electron-rich arylamine, and a preparation method and an application thereof. The ortho-alkylated electron-rich arylamine is characterized in that the structural formula of the ortho-alkylated electron-rich arylamine is represented by formula (I) or formula (I'). The ortho-alkylated electron-rich arylamine is obtained through direct oxidative coupling of arylamine and olefin and selective beta-oxygen or beta-hydrogen elimination of alkyl metal species generated in situ. The preparation method is simple and easily available in substrate, and simple to operate, and can realize efficient synthesis of the electron-rich arylamine derivative; and in view of easily convertible nitrogen-containing groups in the product, the product can be conveniently converted into N-alkyl secondary arylamine, aryl hydrazine and tetrahydroquinoline nitrogen-containing heterocycles, and the application potential of the method is further clarified.
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-
Paragraph 0163-0167
(2020/06/17)
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- Half-Sandwich Ruthenium Complexes for One-Pot Synthesis of Quinolines and Tetrahydroquinolines: Diverse Catalytic Activity in the Coupled Cyclization and Hydrogenation Process
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Four types of half-sandwich ruthenium complexes with an N,O-coordinate mode based on hydroxyindanone-imine ligands have been prepared in good yields. These stable ruthenium complexes exhibited high activity in the catalytic synthesis of quinolines from the reactions of amino alcohols with different types of ketones or secondary alcohols under very mild conditions. Moreover, the methodology for the direct one-pot synthesis of tetrahydroquinoline derivatives from amino alcohols and ketones has been also developed on the basis of the continuous catalytic activity of this ruthenium catalyst in the selective hydrogenation of the obtained quinoline derivatives with a low catalyst loading. The corresponding products, quinolines and tetrahydroquinoline derivatives, were afforded in good to excellent yields. The efficient and diverse catalytic activity of these ruthenium complexes suggested their potential large-scale application. All of the ruthenium complexes were characterized by various spectroscopies to confirm their structures.
- Yun, Xue-Jing,Zhu, Jing-Wei,Jin, Yan,Deng, Wei,Yao, Zi-Jian
-
supporting information
p. 7841 - 7851
(2020/06/04)
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- Method for conducting catalytic hydrogenation on nitrogen-containing unsaturated heterocyclic compound
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The invention provides a method for conducting catalytic hydrogenation on a nitrogen-containing unsaturated heterocyclic compound, and belongs to the technical field of catalytic hydrogenation. The provided method for conducting catalytic hydrogenation on the nitrogen-containing unsaturated heterocyclic compound comprises the following step: in the presence of hydrogen and a manganese catalyst, with the nitrogen-containing unsaturated heterocyclic compound as a substrate, carrying out a hydrogenation reaction. According to the method for conducting catalytic hydrogenation on the nitrogen-containing unsaturated heterocyclic compound, he adopted manganese catalyst is an NNP-type pincer manganese catalyst, has the advantages of being cheap, easy to obtain and low in toxicity compared with noble metal catalysts, has the advantages of being wide in substrate applicability and high in target product yield compared with an existing cheap metal iron catalyst or cobalt catalyst, and is higher in electron donating ability and smaller in steric hindrance compared with a PNP-type pincer manganese catalyst, and thus shows higher reaction activity in a series of hydrogenation reactions, and thetarget product yield is up to 99%.
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-
Paragraph 0094-0104
(2020/01/03)
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- Homogeneous Hydrogenation with a Cobalt/Tetraphosphine Catalyst: A Superior Hydride Donor for Polar Double Bonds and N-Heteroarenes
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The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex-catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24 000 TON and 12 000 h-1 TOF) and excellent chemoselectivities with various aldehydes, ketones, imines, and even N-heteroarenes. The preference for 1,2-reduction over 1,4-reduction makes this method an efficient way to prepare allylic alcohols and amines. Meanwhile, efficient hydrogenation of the challenging N-heteroarenes is also furnished with excellent functional group tolerance. Mechanistic studies and control experiments demonstrated that a CoIH complex functions as a strong hydride donor in the catalytic cycle. Each cobalt intermediate on the catalytic cycle was characterized, and a plausible outer-sphere mechanism was proposed. Noteworthy, external inorganic base plays multiple roles in this reaction and functions in almost every step of the catalytic cycle.
- Duan, Ya-Nan,Du, Xiaoyong,Cui, Zhikai,Zeng, Yiqun,Liu, Yufeng,Yang, Tilong,Wen, Jialin,Zhang, Xumu
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supporting information
p. 20424 - 20433
(2019/12/27)
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- Iridium-Catalyzed Hydrogenation and Dehydrogenation of N-Heterocycles in Water under Mild Conditions
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An efficient catalytic method is presented for the hydrogenation of N-heterocycles. The iridium-based catalyst operates under mild conditions in water without any co-catalyst or stoichiometric additives. The catalyst also promotes the reverse reaction of dehydrogenation of N-heterocycles, hence displaying appropriate characteristics for a future hydrogen economy based on liquid organic hydrogen carriers (LOHCs).
- Wang, Shengdong,Huang, Haiyun,Bruneau, Christian,Fischmeister, Cédric
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p. 2350 - 2354
(2019/05/21)
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- Silver-Catalyzed Reduction of Quinolines in Water
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A ligand- and base-free silver-catalyzed reduction of quinolines and electron-deficient aromatic N-heteroarenes in water has been described. Mechanistic studies revealed that the effective reducing species was Ag-H. This versatile catalytic protocol provided facile, environmentally friendly, and practical access to a variety of 1,2,3,4-tetrahydroquinoline derivatives at room temperature.
- Wang, Yan,Dong, Baobiao,Wang, Zikun,Cong, Xuefeng,Bi, Xihe
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supporting information
p. 3631 - 3634
(2019/05/24)
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- General and Chemoselective Copper Oxide Catalysts for Hydrogenation Reactions
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Copper oxide catalysts have been prepared by pyrolysis of copper acetate on aluminum oxide. The material resulting from pyrolysis at 800 °C allows for catalytic hydrogenations at low temperature of a variety of unsaturated compounds such as quinolines, alkynes, ketones, imines, and polycyclic aromatic hydrocarbons as well as nitroarenes with good activity and selectivity.
- Li, Wu,Cui, Xinjiang,Junge, Kathrin,Surkus, Annette-Enrica,Kreyenschulte, Carsten,Bartling, Stephan,Beller, Matthias
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p. 4302 - 4307
(2019/05/08)
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- Axial-chirality bidentate ligand and application thereof in palladium-catalyzed asymmetric hydrogen transfer reaction
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The invention discloses an axial-chirality bidentate ligand and application thereof in a palladium-catalyzed asymmetric hydrogen transfer reaction. The structural formula of the axial-chirality bidentate ligand is shown in the original specification, wherein R is H, 2, 4, 6-Me, 2, 4, 6-t-Bu and 2, 4, 6-F. The application of the axial-chirality bidentate ligand in the palladium-catalyzed asymmetrichydrogen transfer reaction comprises the following steps: stirring the axial-chirality bidentate ligand and palladium salt in diethyl ether for coordination, concentrating and performing spin drying,so as to obtain a catalyst; adding quinoline into a 10mL single aperture reaction flask, adding chloroform into the reaction flask for dissolving by taking Hantzsch ester, adding 0.01-0.05mol% of thecatalyst into the reaction flask, performing a reaction at room temperature for 6-12h and directly performing column chromatography after the reaction is ended, so as to obtain a target product. According to the axial-chirality bidentate ligand and the application thereof in the palladium-catalyzed asymmetric hydrogen transfer reaction, the technical problem that how the relatively high yield isobtained under a mild condition can be solved.
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-
Paragraph 0020; 0021; 0022; 023
(2019/02/27)
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- A Reusable Cobalt Catalyst for Reversible Acceptorless Dehydrogenation and Hydrogenation of N-Heterocycles
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The development of robust catalytic systems based on base-metals for reversible acceptorless dehydrogenation (ADH) and hydrogenation of feedstock chemicals is very important in the context of ‘hydrogen storage’. Herein, we report a highly efficient reusable cobalt-based heterogeneous catalyst for reversible dehydrogenation and hydrogenation of N-heterocycles. Both the ADH and the hydrogenation processes operate under mild, benign conditions.
- Jaiswal, Garima,Subaramanian, Murugan,Sahoo, Manoj K.,Balaraman, Ekambaram
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p. 2449 - 2457
(2019/05/10)
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- (S)-(?)-Fluorenylethylchloroformate (FLEC); preparation using asymmetric transfer hydrogenation and application to the analysis and resolution of amines
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Fluorenylethylchoroformate (FLEC) is a valuable chiral derivatisation reagent that is used for the resolution of a wide variety of chiral amines. Herein, we describe an improved preparation of (S)-(?)-FLEC using an efficient asymmetric catalytic transfer hydrogenation as the key step. We also demonstrate the application of FLEC as a chiral Fmoc equivalent for chiral resolution, with facile deprotection, of tetrahydroquinaldines, and its capacity for inducing regioselective outcomes in nitration reactions.
- Amin, Mohammad A.,Camerino, Michelle A.,Mountford, Simon J.,Ma, Xiao,Manallack, David T.,Chalmers, David K.,Wills, Martin,Thompson, Philip E.
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- Visible-Light Induction/Br?nsted Acid Catalysis in Relay for the Enantioselective Synthesis of Tetrahydroquinolines
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An efficient method merging Br?nsted acid catalysis with visible-light induction for the highly enantioselective synthesis of tetrahydroquinolines has been developed. This mild process directly transforms 2-aminoenones into 2-substituted tetrahydroquinolines with excellent enantioselectivities through a relay visible-light-induced cyclization/chiral phosphoric acid-catalyzed transfer hydrogenation reaction.
- Xiong, Wenhui,Li, Shan,Fu, Bo,Wang, Jinping,Wang, Qiu-An,Yang, Wen
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p. 4173 - 4176
(2019/06/07)
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- DIRECT C-H AMINATION AND AZA-ANNULATION
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In some aspects, the present disclosure provides methods of aminating an aromatic compound comprising reacting an aminating agent with an aromatic compound in the presence of a rhodium catalyst. In some embodiments, the methods may comprise aminating an aromatic compound which contains multiple different functional groups. The methods described herein may also be used to create bicyclic system comprising reacting an intramolecular aminating agent with an aromatic ring to obtain a second ring containing a nitrogen atom. In another aspect, the methods described herein may also be used to create a cyclic aliphatic cyclic/poly cyclic amine system comprising a reacting an intramolecular aminating agent by insertion into a C(sp3)-H bond.
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-
Paragraph 0132; 0248; 049; 0250
(2019/06/07)
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- Spiro-Bicyclic Bisborane Catalysts for Metal-Free Chemoselective and Enantioselective Hydrogenation of Quinolines
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A new series of spiro-bicyclic bisborane catalysts has been prepared by means of hydroboration reactions of C2-symmetric spiro-bicyclic dienes with HB(C6F5)2 and HB(p-C6F4H)2. When used for hydrogenation of quinolines, these catalysts give excellent yields and enantiomeric excesses, and show turnover numbers of up to 460. The most attractive feature of these metal-free hydrogenation reactions was the broad functional-group tolerance, making this method complementary to existing methods for quinoline hydrogenation.
- Li, Xiang,Tian, Jun-Jie,Liu, Ning,Tu, Xian-Shuang,Zeng, Ning-Ning,Wang, Xiao-Chen
-
supporting information
p. 4664 - 4668
(2019/03/26)
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- Synthesis of spiro-ring bis-boron catalyst and application thereof in hydrogenation reaction
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The invention relates to a synthesis of spiro-ring diene compound with C2 symmetry, and a a series of chirality spiro-ring bis-boron catalysts prepared by virtue of the reaction of the spiro-ring diene compound and boron hydrides. The spiro-ring bis-boron catalysts have high activity and enantioselectivity in the asymmetric hydrogenation reaction of quinoline compounds, and belong to the technicalfield of application. By adopting the synthesis of spiro-ring bis-boron catalyst and the application thereof in hydrogenation reaction, the problems of the traditional quinoline asymmetric hydrogenation reaction method that precious metal catalysts are used and the functional groups are poor in tolerance can be mainly solved, the nonmetal catalytic quinoline asymmetric hydrogenation reaction canbe realized, the reaction substrate range is wide, and the functional group tolerance is high. The synthesis of spiro-ring bis-boron catalyst and the application thereof in hydrogenation reaction areused in the medicine research and chemical production.
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-
Paragraph 0037; 0038; 0039
(2019/04/17)
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- Spiroketal-Based C2-Symmetric Scaffold For Asymmetric Catalysis
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Provided herein is a compound of formula (I): wherein each R is independently selected from the group consisting of C1-8 alkyl, C1-8 heteroalkyl having 1-4 heteroatoms independently selected from N, O, and S, C3-6 cycloalkyl, 3-10 membered heterocycloalkyl having 1-4 heteroatoms independently selected from N, O, and S, C6-10 aryl, and 5-10 membered heteroaryl having 1-4 heteroatoms independently selected from N, O, and S; each X is independently selected from OH, PAr2, P(O)Ar2, OPAr2, C3-6 cycloalkyl, 3-10 membered heterocycloalkyl having 1-4 heteroatoms independently selected from N, O, and S or each X together form O2PNR′2; Ar is C6-10aryl; and each R′ is independently selected from hydrogen and C1-8 alkyl. Also provided are methods of making and using the compound of formula (I).
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-
Paragraph 0143; 0144
(2019/04/08)
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- Breaking Symmetry: Engineering Single-Chain Dimeric Streptavidin as Host for Artificial Metalloenzymes
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The biotin-streptavidin technology has been extensively exploited to engineer artificial metalloenzymes (ArMs) that catalyze a dozen different reactions. Despite its versatility, the homotetrameric nature of streptavidin (Sav) and the noncooperative binding of biotinylated cofactors impose two limitations on the genetic optimization of ArMs: (i) point mutations are reflected in all four subunits of Sav, and (ii) the noncooperative binding of biotinylated cofactors to Sav may lead to an erosion in the catalytic performance, depending on the cofactor:biotin-binding site ratio. To address these challenges, we report on our efforts to engineer a (monovalent) single-chain dimeric streptavidin (scdSav) as scaffold for Sav-based ArMs. The versatility of scdSav as host protein is highlighted for the asymmetric transfer hydrogenation of prochiral imines using [Cp*Ir(biot-p-L)Cl] as cofactor. By capitalizing on a more precise genetic fine-tuning of the biotin-binding vestibule, unrivaled levels of activity and selectivity were achieved for the reduction of challenging prochiral imines. Comparison of the saturation kinetic data and X-ray structures of [Cp*Ir(biot-p-L)Cl]·scdSav with a structurally related [Cp*Ir(biot-p-L)Cl]·monovalent scdSav highlights the advantages of the presence of a single biotinylated cofactor precisely localized within the biotin-binding vestibule of the monovalent scdSav. The practicality of scdSav-based ArMs was illustrated for the reduction of the salsolidine precursor (500 mM) to afford (R)-salsolidine in 90% ee and >17 ?000 TONs. Monovalent scdSav thus provides a versatile scaffold to evolve more efficient ArMs for in vivo catalysis and large-scale applications.
- Wu, Shuke,Zhou, Yi,Rebelein, Johannes G.,Kuhn, Miriam,Mallin, Hendrik,Zhao, Jingming,Igareta, Nico V.,Ward, Thomas R.
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supporting information
p. 15869 - 15878
(2019/10/11)
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- P -Chiral, N -phosphoryl sulfonamide Br?nsted acids with an intramolecular hydrogen bond interaction that modulates organocatalysis
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Br?nsted acids exemplified by OttoPhosa I (5c) were designed and evaluated in the asymmetric transfer hydrogenation of quinolines. Their catalytic properties are modulated by an intramolecular hydrogen bond that rigidifies their catalytic cavity, accelerates the reaction rate and improves enantioselectivity.
- Yuan, Minglei,Mbaezue, Ifenna I.,Zhou, Zhi,Topic, Filip,Tsantrizos, Youla S.
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supporting information
p. 8690 - 8694
(2019/10/16)
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- Highly Selective Hydrogenation with Ionic Liquid Stabilized Nickel Nanoparticles
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Abstract: Nickel nanoparticles (Ni NPs) were conveniently synthesized from the reduction of nickel(II) salt with NaBH4 or hydrazine in the presence of the ionic liquid 1-butyl-2,3-dimethylimidazolium (S)-2-pyrrolidinecarboxylic acid salt. UV/Vis spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy were employed to characterize the interaction between the metal and the ionic liquid. The face-centered cubic structure of the Ni NPs(0) was confirmed by X-ray diffraction characterization. Transmission electron microscopy images revealed well-dispersed Ni particles of approximately 5.1?nm in average diameter. The ionic liquid immobilized Ni NPs were employed as highly efficient catalysts in chemoselective hydrogenation of quinoline and relevant compounds, as well as aromatic nitro compounds under mild reaction conditions. The Ni NPs can be efficiently recovered and reused. Graphical Abstract: [Figure not available: see fulltext.]
- Jiang, He-yan,Zhang, Si-shi,Sun, Bin
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p. 1336 - 1344
(2018/03/26)
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- Selective hydrogenation of aromatic compounds using modified iridium nanoparticles
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Till now, Ionic liquid-stabilized metal nanoparticles were investigated as catalytic materials, mostly in the hydrogenation of simple substrates like olefins or arenes. The adjustable hydrogenation products of aromatic compounds, including quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes, are always of special interest, since they provide more choices for additional derivatization. Iridium nanoparticles (Ir NPs) were synthesized by the H2 reduction in imidazolium ionic liquid. TEM indicated that the Ir NPs is worm-like shape with the diameter around 12.2?nm and IR confirmed the modification of phosphine-functionalized ionic liquids (PFILs) to the Ir NPs. With the variation of the modifier, solvent and reaction temperature, substrate like quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes could be hydrogenated by Ir NPs with interesting adjustable catalytic activity and chemoselectivity. Ir NPs modified by PFILs are simple and efficient catalysts in challenging chemoselective hydrogenation of quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes. The activity and chemoselectivity of the Ir NPs could be obviously impacted or adjusted by altering the modifier, solvent and reaction temperature.
- Jiang, He-Yan,Xu, Jie,Sun, Bin
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- Versatile Rh- and Ir-Based Catalysts for CO2 Hydrogenation, Formic Acid Dehydrogenation, and Transfer Hydrogenation of Quinolines
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Considering the interest in processes related to hydrogen storage such as CO2 hydrogenation and formic acid (FA) decomposition, we have synthesized a set of Ir, Rh, or Ru complexes to be tested as versatile precatalysts in these reactions. In relation with the formation of H2 from FA, the possible applicability of these complexes in the transfer hydrogenation (TH) of challenging substrates as quinoline derivatives using FA/formate as hydrogen donor has also been addressed. Bearing in mind the importance of secondary coordination sphere interactions, N,N′ ligands containing NH2 groups, coordinated or not to the metal center, were used. The general formula of the new complexes are [(p-cymene)RuCl(N,N′)]X, X = Cl-, BF4- and [Cp?MCl(N,N′)]Cl, M = Rh, Ir, where the N,N′ ligands are 8-aminoquinoline (HL1), 6-pyridyl-2,4-diamine-1,3,5-triazine (L2) and 5-amino-1,10-phenanthroline (L3). Some complexes are not active or catalyze only one process. However, the complexes [Cp?MCl(HL1)]Cl with M = Rh, Ir are versatile catalysts that are active in hydrogenation of quinolines, FA decomposition, and also in CO2 hydrogenation with the iridium derivative being more active and robust. The CO2 hydrogenation takes place in mild conditions using only 5 bar of pressure of each gas (CO2 and H2). The behavior of some precatalysts in D2O and after the addition of 9 equiv of HCO2Na (pseudocatalytic conditions) has been studied in detail and mechanisms for the FA decomposition and the hydrogenation of CO2 have been proposed. For the Ru, Ir, or Rh complexes with ligand HL1, the amido species with the deprotonated ligand are observed. In the case of ruthenium, the formate complex is also detected. For the iridium derivative, both the amido intermediate and the hydrido species have been observed. This hydrido complex undergoes a process of umpolung D+a?" Ir-D. All in all, the results of this work reflect the active role of aNH2 in the transfer of H+.
- Fidalgo, Jairo,Ruiz-Castaneda, Margarita,García-Herbosa, Gabriel,Carbayo, Arancha,Jalón, Félix A.,Rodríguez, Ana M.,Manzano, Blanca R.,Espino, Gustavo
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p. 14186 - 14198
(2018/11/23)
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- A robust iron catalyst for the selective hydrogenation of substituted (iso)quinolones
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By applying N-doped carbon modified iron-based catalysts, the controlled hydrogenation of N-heteroarenes, especially (iso)quinolones, is achieved. Crucial for activity is the catalyst preparation by pyrolysis of a carbon-impregnated composite, obtained from iron(ii) acetate and N-aryliminopyridines. As demonstrated by TEM, XRD, XPS and Raman spectroscopy, the synthesized material is composed of Fe(0), Fe3C and FeNx in a N-doped carbon matrix. The decent catalytic activity of this robust and easily recyclable Fe-material allowed for the selective hydrogenation of various (iso)quinoline derivatives, even in the presence of reducible functional groups, such as nitriles, halogens, esters and amides. For a proof-of-concept, this nanostructured catalyst was implemented in the multistep synthesis of natural products and pharmaceutical lead compounds as well as modification of photoluminescent materials. As such this methodology constitutes the first heterogeneous iron-catalyzed hydrogenation of substituted (iso)quinolones with synthetic importance.
- Sahoo, Basudev,Kreyenschulte, Carsten,Agostini, Giovanni,Lund, Henrik,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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p. 8134 - 8141
(2018/11/20)
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- Nanolayered Cobalt-Molybdenum Sulfides as Highly Chemo- and Regioselective Catalysts for the Hydrogenation of Quinoline Derivatives
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Herein, a general protocol for the preparation of a broad range of valuable N-heterocyclic products by hydrogenation of quinolines and related N-heteroarenes is described. Interestingly, the catalytic hydrogenation of the N-heteroarene ring is chemoselectively performed when other facile reducible functional groups, including alkenes, ketones, cyanides, carboxylic acids, esters, and amides, are present. The key to successful catalysis relies on the use of a nanolayered cobalt-molybdenum sulfide catalyst hydrothermally synthesized from earth-abundant metal precursors. This heterogeneous system displays a tunable composition of phases that allows for catalyst regeneration. Its catalytic activity depends on the composition of the mixed phase of cobalt sulfides, being higher with the presence of Co3S4, and could also be associated with the presence of transient Co-Mo-S structures that mainly vanish after the first catalytic run.
- Sorribes, Iván,Liu, Lichen,Doménech-Carbó, Antonio,Corma, Avelino
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p. 4545 - 4557
(2018/05/22)
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- Ordered Porous Nitrogen-Doped Carbon Matrix with Atomically Dispersed Cobalt Sites as an Efficient Catalyst for Dehydrogenation and Transfer Hydrogenation of N-Heterocycles
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Single-atom catalysts (SACs) have been explored widely as potential substitutes for homogeneous catalysts. Isolated cobalt single-atom sites were stabilized on an ordered porous nitrogen-doped carbon matrix (ISAS-Co/OPNC). ISAS-Co/OPNC is a highly efficient catalyst for acceptorless dehydrogenation of N-heterocycles to release H2. ISAS-Co/OPNC also exhibits excellent catalytic activity for the reverse transfer hydrogenation (or hydrogenation) of N-heterocycles to store H2, using formic acid or external hydrogen as a hydrogen source. The catalytic performance of ISAS-Co/OPNC in both reactions surpasses previously reported homogeneous and heterogeneous precious-metal catalysts. The reaction mechanisms are systematically investigated using first-principles calculations and it is suggested that the Eley–Rideal mechanism is dominant.
- Han, Yunhu,Wang, Ziyun,Xu, Ruirui,Zhang, Wei,Chen, Wenxing,Zheng, Lirong,Zhang, Jian,Luo, Jun,Wu, Konglin,Zhu, Youqi,Chen, Chen,Peng, Qing,Liu, Qiang,Hu,Wang, Dingsheng,Li, Yadong
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supporting information
p. 11262 - 11266
(2018/08/28)
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