1780-19-4Relevant articles and documents
Iridium-catalyzed hydrogenation of N-heterocyclic compounds under mild conditions by an outer-sphere pathway
Dobereiner, Graham E.,Nova, Ainara,Schley, Nathan D.,Hazari, Nilay,Miller, Scott J.,Eisenstein, Odile,Crabtree, Robert H.
, p. 7547 - 7562 (2011)
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.
Highly enantioselective iridium-catalyzed hydrogenation of quinoline derivatives using chiral phosphinite H8-BINAPO
Kim, Hung Lam,Xu, Lijin,Feng, Lichun,Fan, Qing-Hua,Fuk, Loi Lam,Lo, Wai-Hung,Chan, Albert S. C.
, p. 1755 - 1758 (2005)
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.
Novel Ir-SYNPHOS and Ir-DIFLUORPHOS catalysts for asymmetric hydrogenation of quinolines
Deport, Coralie,Buchotte, Marie,Abecassis, Keren,Tadaoka, Hiroshi,Ayad, Tahar,Ohshima, Takashi,Genet, Jean-Pierre,Mashima, Kazushi,Ratovelomanana-Vidal, Virginie
, p. 2743 - 2747 (2007)
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.
Iridium-catalyzed asymmetric transfer hydrogenation of quinolines with Hantzsch esters
Wang, Da-Wei,Zeng, Wei,Zhou, Yong-Gui
, p. 1103 - 1107 (2007)
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.
Asymmetric hydrogenation of heteroaromatic compounds mediated by iridium-(P-OP) complexes
Nunez-Rico, Jose L.,Fernandez-Perez, Hector,Benet-Buchholz,Vidal-Ferran, Anton
, p. 6627 - 6631 (2010)
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).
Asymmetric hydrogenation of quinolines catalyzed by iridium with chiral ferrocenyloxazoline derived N,P ligands
Lu, Sheng-Mei,Han, Xiu-Wen,Zhou, Yong-Gui
, p. 909 - 912 (2004)
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.
Inhibiting deactivation of iridium catalysts with bulky substituents on coordination atoms
Wang, Duo-Sheng,Zhou, Juan,Wang, Da-Wei,Guo, Yin-Long,Zhou, Yong-Gui
, p. 525 - 528 (2010)
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
Enantioselective hydrogenation of quinolines catalyzed by Ir(BINAP)-cored dendrimers: Dramatic enhancement of catalytic activity
Wang, Zhi-Jian,Deng, Guo-Jun,Li, Yong,He, Yan-Mei,Tang, Wei-Jun,Fan, Qing-Hua
, p. 1243 - 1246 (2007)
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.
Synthesis of new amidophosphite ligand and its application in Ir-catalyzed asymmetric hydrogenation of heterocyclic compounds
Lyubimov,Ozolin,Pavlov,Fedorova,Velezheva,Davankov
, p. 1405 - 1408 (2013)
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.
RUTHENIUM CATALYZED REDUCTION OF NITROARENES AND AZAAROMATIC COMPOUNDS USING FORMIC ACID.
Watanabe,Ohta,Tsuji,Hiyoshi,Tsuji
, p. 2440 - 2444 (1984)
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.
Asymmetric hydrogenation of quinolines catalyzed by iridium complexes of BINOL-derived diphosphonites
Reetz, Manfred T.,Li, Xiaoguang
, p. 2159 - 2160 (2006)
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.
Kinetic resolution of (±)-2-methyl-1,2,3,4-tetrahydroquinoline and (±)-2-methylindoline
Krasnov, Victor P.,Levit, Galina L.,Andreeva, Irina N.,Grishakov, Alexander N.,Charushin, Valery N.,Chupakhin, Oleg N.
, p. 27 - 28 (2002)
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.
Synthesis of tunable bisphosphine ligands and their application in asymmetric hydrogenation of quinolines
Wang, Xiao-Bing,Zhou, Yong-Gui
, p. 5640 - 5642 (2008)
(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.
Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N-Ferrocenyl NHC-Iridium Complex
John, Joshni,Wilson-Konderka, Cody,Metallinos, Costa
, p. 2071 - 2081 (2015)
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.
Oxygen-implanted MoS2 nanosheets promoting quinoline synthesis from nitroarenes and aliphatic alcohols via an integrated oxidation transfer hydrogenation-cyclization mechanism
Gao, Zhuyan,Huang, Zhipeng,Lu, Jianmin,Mu, Junju,Ren, Puning,Su, Kaiyi,Wang, Feng,Zhang, Chaofeng,Zhang, Shichao
supporting information, p. 1704 - 1713 (2022/03/08)
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.
Pd/c catalyzed decarboxylation-transfer hydrogenation of quinoline carboxylic acids
Zhou, Xiao-Yu,Chen, Xia
, p. 625 - 633 (2021/09/30)
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.
Method for preparing tetrahydroquinoline compounds by catalytic hydrogenation of ruthenium catalyst
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Paragraph 0030-0033, (2021/01/29)
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.
