16071-25-3Relevant academic research and scientific papers
Bio-inspired asymmetric aldehyde arylations catalyzed by rhodium-cyclodextrin self-inclusion complexes
Asahi, Kaoru,Fujiwara, Shin-Ichi,Iwasaki, Takanori,Kambe, Nobuaki,Takahashi, Ryota,Tsuda, Susumu,Ueda, Ryoji,Yamauchi, Hiroki
supporting information, p. 801 - 807 (2022/02/03)
Transition-metal catalysts are powerful tools for carbon-carbon bond-forming reactions that are difficult to achieve using native enzymes. Enzymes that exhibit inherent selectivities and reactivities through host-guest interactions have inspired widesprea
Preparation method of cetirizine impurity C
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Paragraph 0052-0055; 0068-0070; 0075-0077, (2022/01/10)
The present invention relates to the field of pharmaceutical chemical technology, specifically, to a method for preparing cetirizine impurity C. The method is to prepare the key intermediate 4-{(2-chlorophenyl)phenyl) directly with hydroxyethylpiperazine
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.
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.
Chiral amino-pyridine-phosphine tridentate ligand, manganese complex, and preparation method and application thereof
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Paragraph 0597-0600; 0605, (2020/07/13)
The invention discloses a chiral amino-pyridine-phosphine tridentate ligand, a manganese complex, and a preparation method and application thereof. The chiral amino-pyridine-phosphine tridentate ligand is shown as a formula II, and the manganese complex of the chiral amino-pyridine-phosphine tridentate ligand can be used for efficiently catalyzing and hydrogenating ketone compounds to prepare chiral alcohol compounds in a high enantioselectivity mode. The chiral amino-pyridine-phosphine tridentate ligand and the manganese complex are simple in synthesis process, good in stability, high in catalytic activity and mild in reaction conditions.
Highly Enantioselective Cobalt-Catalyzed Hydroboration of Diaryl Ketones
Liu, Wenbo,Guo, Jun,Xing, Shipei,Lu, Zhan
supporting information, p. 2532 - 2536 (2020/04/02)
A highly enantioselective cobalt-catalyzed hydroboration of diaryl ketones with pinacolborane was developed using chiral imidazole iminopyridine as a ligand to access chiral benzhydrols in good to excellent yields and ee. This protocol could be carried out in a gram scale under mild reaction conditions with good functional group tolerance. Chiral biologically active 3-substituted phthalide and (S)-neobenodine could be easily constructed through asymmetric hydroboration as a key step.
Redox-driven deracemization of secondary alcohols by sequential ether/O2-mediated oxidation and Ru-catalyzed asymmetric reduction
Yang, Bing,Cui, Peng,Chen, Yongsheng,Liu, Qixing,Zhou, Haifeng
supporting information, (2020/10/14)
The deracemization of benzylic alcohols has been achieved using a redox-driven one-pot two-step process. The racemic alcohols were oxidized by bis(methoxypropyl) ether and oxygen to give the ketone intermediates, followed by an asymmetric transfer hydrogenation with a chiral ruthenium catalyst. This compatible oxidation/reduction process gave the enantiomerically enriched alcohols with up to 95% ee values.
Asymmetric hydrogenation method of di (hetero) aryl ketone compound
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Paragraph 0110-0116, (2020/12/08)
The invention belongs to the technical field of chemical synthesis preparation, relates to asymmetric catalysis of compounds, and particularly relates to an asymmetric hydrogenation method of a di (hetero) aryl ketone compound. The asymmetric hydrogenatio
Engineering an alcohol dehydrogenase with enhanced activity and stereoselectivity toward diaryl ketones: Reduction of steric hindrance and change of the stereocontrol element
Chen, Rong,Huang, Jiankun,Meng, Xiangguo,Shao, Lei,Wu, Kai,Yang, Zhijun
, p. 1650 - 1660 (2020/04/09)
Steric hindrance in the binding pocket of an alcohol dehydrogenase (ADH) has a great impact on its activity and stereoselectivity simultaneously. Due to the subtle structural difference between two bulky phenyl substituents, the asymmetric synthesis of diaryl alcohols by bioreduction of diaryl ketones is often hindered by the low activity and stereoselectivity of ADHs. To engineer an ADH with practical properties and to investigate the molecular mechanism behind the asymmetric biocatalysis of diaryl ketones, we engineered an ADH from Lactobacillus kefiri (LkADH) to asymmetrically catalyse the reduction of 4-chlorodiphenylketones (CPPK), which are not catalysed by the wild type (WT) enzyme. Mutants seq1-seq5 with gradually increased activity and stereoselectivity were obtained through iterative "shrinking mutagenesis." The final mutant seq5 (Y190P/I144V/L199V/E145C/M206F) demonstrated the highest activity and excellent stereoselectivity of >99% ee. Molecular simulation analyses revealed that mutations may enhance the activity by eliminating steric hindrance, inducing a more open binding loop and constructing more noncovalent interactions. The pro-R pose of CPPK with a halogen bond formed a pre-reaction conformation more easily than the pro-S pose, resulting in the high ee of (R)-CPPO in seq5. Moreover, different halogen bonds formed due to the different positions of chlorine substituents, resulting in opposite substrate binding orientation and stereoselectivity. Therefore, the stereoselectivity of seq5 was inverted toward ortho- rather than para-chlorine substituted ketones. These results indicate that the stereocontrol element of LkADH was changed to recognise diaryl ketones after steric hindrance was eliminated. This study provides novel insights into the role of steric hindrance and noncovalent bonds in the determination of the activity and stereoselectivity of enzymes, and presents an approach producing key intermediates of chiral drugs with practical potential.
Lutidine-Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones
Zhang, Linli,Tang, Yitian,Han, Zhaobin,Ding, Kuiling
supporting information, p. 4973 - 4977 (2019/03/17)
A series of MnI complexes containing lutidine-based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional-group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth-abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs. Preliminary mechanistic investigations indicate that an outer-sphere mode of substrate–catalyst interactions probably dominates the catalysis.
