127733-44-2Relevant academic research and scientific papers
Asymmetric hydrogenation of aromatic ketones catalysed by L-proline derivatives modified Ru/γ-Al2OO
Jiang, Heyan
, p. 410 - 413 (2014)
The asymmetric hydrogenation of aromatic ketones catalysed by L-proline derivative- and PPh3-modified 1.0%Ru/γ-Al2OO was studied. The effects of different stabilisers, P/Ru ratio, modifiers, modifier concentration, solvents, base additives and base concentration on the asymmetric hydrogenation of aromatic ketones were investigated. The results showed that L-proline derivatives had good modification effects on the 1.0%Ru/γ- Al2OO/2tpp catalyst. Under optimum conditions, the hydrogenation enantioselectivity of acetophenone was 70%. The enantioselectivity of the hydrogenation product of propiophenone could reach 81%.
Thioureas: New ligands for the metal catalyzed asymmetric reduction of carbonyl compounds
Touchard, Francois,Fache, Fabienne,Lemaire, Marc
, p. 3319 - 3326 (1997)
The catalytic enantioselective hydride transfer reduction of prochiral ketones using differently substituted mono and dithioureas with several catalyst precursors is reported. The best results are obtained with a ruthenium complex and a C2 symmetric ligand.
Hydrogenation of acetophenone derivatives: Tuning the enantioselectivity via the metal-support interaction
Hoxha, Fatos,Schmidt, Erik,Mallat, Tamas,Schimmoeller, Bjoern,Pratsinis, Sotiris E.,Baiker, Alfons
, p. 94 - 101 (2011)
The influence of acidic and basic supports on the enantioselective hydrogenation of acetophenone and its aryl-substituted derivates was studied. The Pt/Al2O3, Pt/Al2O3-SiO 2, and Pt/Al2O3-Cs2O catalysts were prepared by single-step flame spray pyrolysis, and cinchonidine (CD) was used as chiral modifier. For all five aromatic ketones, the acidic support improved the ee, while the basic support diminished it. Opposite tendencies were observed for the reaction rate: acidic support lowered and basic support enhanced the rate of ketone conversion. In situ investigation of the hydrogenation of the quinoline ring of CD revealed for the first time that degradation of the modifier leads to remarkable variation in the substrate/modifier ratio. This effect and a possible catalyst deactivation due to aldol condensation of the ketones may be the origin of the decrease in ee with conversion. Following the diastereoselectivity during hydrogenation of the heteroaromatic ring of the quinoline unit of CD proved dominantly pro(S) adsorption mode on Pt/Al 2O3 and Pt/Al2O3-SiO2, and pro(R) on Pt/Al2O3-Cs2O catalysts. Changes in the adsorption mode were minor during hydrogenation of aromatic ketones. This, together with the small effect of ketones on the hydrogenation rate of CD, is interpreted as an indication to weak substrate-modifier interactions, in contrast to the situation during the hydrogenation of α-ketoesters (methyl benzoylformate).
One-Pot Chemoenzymatic Conversion of Alkynes to Chiral Amines
Mathew, Sam,Renn, Dominik,Rueping, Magnus,Sagadevan, Arunachalam
, p. 12565 - 12569 (2021/10/21)
A one-pot chemoenzymatic sequential cascade for the synthesis of chiral amines from alkynes was developed. In this integrated approach, just ppm amounts of gold catalysts enabled the conversion of alkynes to ketones (>99%) after which a transaminase was used to catalyze the production of biologically valuable chiral amines in a good yield (up to 99%) and enantiomeric excess (>99%). A preparative scale synthesis of (S)-methylbenzylamine and (S)-4-methoxy-methylbenzylamine from its alkyne form gave a yield of 59 and 92%, respectively, withee> 99%.
Mn(i) phosphine-amino-phosphinites: a highly modular class of pincer complexes for enantioselective transfer hydrogenation of aryl-alkyl ketones
Jayaprakash, Harikrishnan
supporting information, p. 14115 - 14119 (2021/10/25)
A series of Mn(i) catalysts with readily accessible and more π-accepting phosphine-amino-phosphinite (P′(O)N(H)P) pincer ligands have been explored for the asymmetric transfer hydrogenation of aryl-alkyl ketones which led to good to high enantioselectivities (up to 98%) compared to other reported Mn-based catalysts for such reactions. The easy tunability of the chiral backbone and the phosphine moieties makes P′(O)N(H)P an alternative ligand framework to the well-known PNP-type pincers.
A Cobalt(II) Complex Bearing the Amine(imine)diphosphine PN(H)NP Ligand for Asymmetric Transfer Hydrogenation of Ketones
Huo, Shangfei,Chen, Hong,Zuo, Weiwei
supporting information, p. 37 - 42 (2020/10/21)
Novel chiral cobalt complex a containing amine(imine)diphosphine PN(H)NP ligand and complex b containing bis(amine)diphosphine PN(H)N(H)P ligand were synthesized. The structures of two complexes were characterized by X-ray crystallography and high resolution mass spectrometry. The catalytic performances of cobalt complexes a and b for asymmetric transfer hydrogenation (ATH) of ketones under mild conditions were evaluated using 2-propanolisopropanol as solvent and hydrogen source after being activated by 8 equivalents of base. Complex a showed a good reactivity for reduction of ketones, with a turnover number (TON) of up to 555, and a maximum enantiomeric excess (ee) value of up to 91 %. Complex b exhibited inertness for hydrogenation of ketones. Electronic structure studies on a and b were conducted to account for the function of ligands on the catalytic performances.
Cinchona-Alkaloid-Derived NNP Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
Chen, Qian,Jiang, Jian,Li, Chun,Li, Linlin,Sun, Hao,Yang, Yuanyong,Zhang, Lin,Zhang, Ling,Zhao, Chong
supporting information, (2022/01/12)
Most ligands applied for asymmetric hydrogenation are synthesized via multistep reactions with expensive chemical reagents. Herein, a series of novel and easily accessed cinchona-alkaloid-based NNP ligands have been developed in two steps. By combining [Ir(COD)Cl]2, 39 ketones including aromatic, heteroaryl, and alkyl ketones have been hydrogenated, all affording valuable chiral alcohols with 96.0-99.9% ee. A plausible reaction mechanism was discussed by NMR, HRMS, and DFT, and an activating model involving trihydride was verified.
Manganese catalyzed asymmetric transfer hydrogenation of ketones
Zhang, Guang-Ya,Ruan, Sun-Hong,Li, Yan-Yun,Gao, Jing-Xing
supporting information, p. 1415 - 1418 (2020/11/20)
The asymmetric transfer hydrogenation (ATH) of a wide range of ketones catalyzed by manganese complex as well as chiral PxNy-type ligand under mild conditions was investigated. Using 2-propanol as hydrogen source, various ketones could be enantioselectively hydrogenated by combining cheap, readily available [MnBr(CO)5] with chiral, 22-membered macrocyclic ligand (R,R,R',R')-CyP2N4 (L5) with 2 mol% of catalyst loading, affording highly valuable chiral alcohols with up to 95% ee.
Ruthenium-catalyzed hydrogenation of aromatic ketones using chiral diamine and monodentate achiral phosphine ligands
Wang, Mengna,Zhang, Ling,Sun, Hao,Chen, Qian,Jiang, Jian,Li, Linlin,Zhang, Lin,Li, Li,Li, Chun
, (2021/03/24)
The Ru-catalyzed asymmetric hydrogenation of ketones with chiral diamine and monodentate achiral phosphine has been developed. A wide range of ketones were hydrogenated to afford the corresponding chiral secondary alcohols in good to excellent enantioselectivities (up to 98.1% ee). In addition, an appropriate mechanism for the asymmetric hydrogenation was proposed and verified by NMR spectroscopy.
Tridentate nitrogen phosphine ligand containing arylamine NH as well as preparation method and application thereof
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Paragraph 0095-0102; 0105-0109, (2021/06/26)
The invention discloses a tridentate nitrogen phosphine ligand containing arylamine NH as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis. The tridentate nitrogen phosphine ligand disclosed by the invention is the first case of tridentate nitrogen phosphine ligand containing not only a quinoline amine structure but also chiral ferrocene at present, a noble metal complex of the type of ligand shows good selectivity and extremely high catalytic activity in an asymmetric hydrogenation reaction, meanwhile, a cheap metal complex of the ligand can also show good selectivity and catalytic activity in the asymmetric hydrogenation reaction, and is very easy to modify in the aspects of electronic effect and space structure, so that the ligand has huge potential application value. A catalyst formed by the ligand and a transition metal complex can be used for catalyzing various reactions, can be used for synthesizing various drugs, and has important industrial application value.
