132437-66-2Relevant academic research and scientific papers
Chiral and nonchiral [OsX2(diphosphane)(diamine)] (X: Cl, OCH2CF3) complexes for fast hydrogenation of carbonyl compounds
Baratta, Walter,Barbato, Cinzia,Magnolia, Santo,Siega, Katia,Rigo, Pierluigi
, p. 3201 - 3206 (2010)
The osmium complexes trans-[OsCl2(dppf)(diamine)] (dppf: 1,1′-bis(diphenylphosphino)ferrocene; diamine: ethylenediamine in 3, propylenediamine in 4) were prepared by the reaction of [OsCl 2(PPh3)3] (1) with the ferrocenyl diphosphane, dppf and the corresponding diamine in dichloromethane. The reaction of derivative 3 with NaOCH2CF3 in toluene afforded the alkoxide cis-[Os(OCH2CF3)2(dppf) (ethylenediamine)] (5). The novel precursor [Os2Cl 4(P(m-tolyl)3)5] (2) allows the synthesis of the chiral complexes trans-[OsCl2(diphosphane)(1,2-diamine)] (6-9; diphosphane: (R)-[6,6′dimethoxy(1,1′-biphenyl)-2,2′-diyl] bis[1,1-bis(3,5-dimethylphenyl)phosphane] (xylMeObiphep) or (R)-(1,1′- binaphthalene)-2,2′-diylbis[1,1-bis(3,5-dimethylphenyl)phosphane] (xylbinap); diamine = (R,R)-1,2-diphenylethylenediamine (dpen) or (R,R)-l,2-diaminocyclohexane (dach)), obtained by the treatment of 2 with the diphosphane and the 1,2-diamine in toluene at reflux temperature. Compounds 3-5 in ethanol and in the presence of NaOEt catalyze the reduction of methyl aryl, dialkyl, and diaryl ketones and aldehydes with H2 at low pressure (5 atm), with substrate/catalyst (S/C) ratios of 10000-200000 and achieving turnover frequencies (TOFs) of up to 3.0x 105 h-1 at 70°C. By employment of the chiral compounds 6-9, different ketones, including alkyl aryl, bulky tertbutyl, and cyclic ketones, have successfully been hydrogenated with enantioselectivities up to 99% and with S/C ratios of 5000-100000 and TOFs of up to4.1xl04h-1at 60°C.
Enhancing cofactor regeneration of cyanobacteria for the light-powered synthesis of chiral alcohols
Fan, Jianhua,Zhang, Yinghui,Wu, Ping,Zhang, Xiaoyan,Bai, Yunpeng
, (2021/11/24)
Cyanobacteria Synechocystis sp. PCC 6803 was exploited as green cell factory for light-powered asymmetric synthesis of aromatic chiral alcohols. The effect of temperature, light, substrate and cell concentration on substrate conversions were investigated. Under the optimal condition, a series of chiral alcohols were synthesized with conversions up to 95% and enantiomer excess (ee) > 99%. We found that the addition of Na2S2O3 and Angeli's Salt increased the NADPH content by 20% and 25%, respectively. As a result, the time to reach 95% substrate conversion was shortened by 12 h, which demonstrated that the NADPH regeneration and hence the reaction rates can be regulated in cyanobacteria. This blue-green algae based biocatalysis showed its potential for chiral compounds production in future.
Cinchona-Alkaloid-Derived NNP Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
Zhang, Lin,Zhang, Ling,Chen, Qian,Li, Linlin,Jiang, Jian,Sun, Hao,Zhao, Chong,Yang, Yuanyong,Li, Chun
supporting information, p. 415 - 419 (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.
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.
Highly Active Cooperative Lewis Acid—Ammonium Salt Catalyst for the Enantioselective Hydroboration of Ketones
Titze, Marvin,Heitk?mper, Juliane,Junge, Thorsten,K?stner, Johannes,Peters, René
supporting information, p. 5544 - 5553 (2021/02/05)
Enantiopure secondary alcohols are fundamental high-value synthetic building blocks. One of the most attractive ways to get access to this compound class is the catalytic hydroboration. We describe a new concept for this reaction type that allowed for exceptional catalytic turnover numbers (up to 15 400), which were increased by around 1.5–3 orders of magnitude compared to the most active catalysts previously reported. In our concept an aprotic ammonium halide moiety cooperates with an oxophilic Lewis acid within the same catalyst molecule. Control experiments reveal that both catalytic centers are essential for the observed activity. Kinetic, spectroscopic and computational studies show that the hydride transfer is rate limiting and proceeds via a concerted mechanism, in which hydride at Boron is continuously displaced by iodide, reminiscent to an SN2 reaction. The catalyst, which is accessible in high yields in few steps, was found to be stable during catalysis, readily recyclable and could be reused 10 times still efficiently working.
Pushing the limits: Cyclodextrin-based intensification of bioreductions
Rapp, Christian,Nidetzky, Bernd,Kratzer, Regina
, p. 57 - 64 (2020/12/02)
The asymmetric reduction of ketones is a frequently used synthesis route towards chiral alcohols. Amongst available chemo- and biocatalysts the latter stand out in terms of product enantiopurity. Their application is, however, restricted by low reaction output, often rooted in limited enzyme stability under operational conditions. Here, addition of 2-hydroxypropyl-β-cyclodextrin to bioreductions of o-chloroacetophenone enabled product concentrations of up to 29 % w/v at full conversion and 99.97 % e.e. The catalyst was an E. coli strain co-expressing NADH-dependent Candida tenuis xylose reductase and a yeast formate dehydrogenase for coenzyme recycling. Analysis of the lyophilized biocatalyst showed that E. coli cells were leaky with catalytic activity found as free-floating enzymes and associated with the biomass. The biocatalyst was stabilized and activated in the reaction mixture by 2-hydroxypropyl-β-cyclodextrin. Substitution of the wild-type xylose reductase by a D51A mutant further improved bioreductions. In previous optimization strategies, hexane was added as second phase to protect the labile catalyst from adverse effects of hydrophobic substrate and product. The addition of 2-hydroxypropyl-β-cyclodextrin (11 % w/v) instead of hexane (20 % v/v) increased the yield on biocatalyst 6.3-fold. A literature survey suggests that bioreduction enhancement by addition of cyclodextrins is not restricted to specific enzyme classes, catalyst forms or substrates.
Single-Point Mutant Inverts the Stereoselectivity of a Carbonyl Reductase toward β-Ketoesters with Enhanced Activity
Li, Aipeng,Wang, Ting,Tian, Qing,Yang, Xiaohong,Yin, Dongming,Qin, Yong,Zhang, Lianbing
, p. 6283 - 6294 (2021/03/16)
Enzyme stereoselectivity control is still a major challenge. To gain insight into the molecular basis of enzyme stereo-recognition and expand the source of antiPrelog carbonyl reductase toward β-ketoesters, rational enzyme design aiming at stereoselectivity inversion was performed. The designed variant Q139G switched the enzyme stereoselectivity toward β-ketoesters from Prelog to antiPrelog, providing corresponding alcohols in high enantiomeric purity (89.1–99.1 % ee). More importantly, the well-known trade-off between stereoselectivity and activity was not found. Q139G exhibited higher catalytic activity than the wildtype enzyme, the enhancement of the catalytic efficiency (kcat/Km) varied from 1.1- to 27.1-fold. Interestingly, the mutant Q139G did not lead to reversed stereoselectivity toward aromatic ketones. Analysis of enzyme–substrate complexes showed that the structural flexibility of β-ketoesters and a newly formed cave together facilitated the formation of the antiPrelog-preferred conformation. In contrast, the relatively large and rigid structure of the aromatic ketones prevents them from forming the antiPrelog-preferred conformation.
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.
Biocatalytic preparation of a key intermediate of antifungal drugs using an alcohol dehydrogenase with high organic tolerance
Yan, Jinrong,Wang, Xiaojing,Li, Fangling,Yang, Lei,Shi, Guixiang,Sun, Weihang,Shao, Lei,Huang, Junhai,Wu, Kai
supporting information, (2021/10/20)
In this study, an alcohol dehydrogenase derived from Lactobacillus kefir (LkADH) was engineered and a simple and practical bioreduction system was developed for the preparation of (R)-2-chloro-1-(2, 4-dichlorophenyl) ethanol ((R)-CDPO), a key intermediate for the synthesis of antifungal drugs. Through active pocket iterative saturation mutagenesis, mutant LkADH-D18 (Y190C/V196L/M206H/D150H) was obtained with high stereoselectivity (99% ee, R vs 87% ee, S) and increased activity (0.44 μmol·min?1·mg?1). LkADH-D18 demonstrated NAD(P)H regeneration capability using a high concentration of isopropanol (IPA) as a co-substrate. Using 40% IPA (v/v), 400 mM of (R)-CDPO (90.1 g·L-1) was obtained via complete substrate conversion using 40 mg·mL?1 LkADH-D18 wet cells. The biocatalytic process catalyzed at constant pH with the cheap co-solvent IPA contributed to improved isolated yield of (R)-CDPO (97%), lower reaction cost, and simpler downstream purification, indicating the potential utility of LkADH-D18 in future industrial applications.
CO2-expanded liquids as solvents to enhance activity of Pseudozyma antarctica lipase B towards ortho-substituted 1-phenylethanols
Hoang, Hai Nam,Koesoema, Afifa Ayu,Matsuda, Tomoko,Otsu, Moeko,Suzuki, Yuichi,Tamura, Mayumi
supporting information, (2020/09/18)
Pseudozyma (Candida) antarctica lipase B (CAL-B, Novozym 435) is one of the most widely used and outstanding biocatalysts. However, CAL-B-catalyzed transesterification of ortho-substituted 1-phenylethanol analogs suffers low conversion. In this research, the reactions were accelerated by using CO2-expanded liquids, liquids expanded by dissolving pressurized CO2, such as CO2-expanded hexane or CO2-expanded MeTHF.
