112653-32-4Relevant academic research and scientific papers
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.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
, p. 247 - 251 (2020/10/29)
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
Phase Separation-Promoted Redox Deracemization of Secondary Alcohols over a Supported Dual Catalysts System
Zhao, Zhitong,Wang, Chengyi,Chen, Qipeng,Wang, Yu,Xiao, Rui,Tan, Chunxia,Liu, Guohua
, p. 4055 - 4063 (2021/08/12)
Unification of oxidation and reduction in a one-pot deracemization process has great significance in the preparation of enantioenriched organic molecules. However, the intrinsic mutual deactivation of oxidative and reductive catalysts and the extrinsic incompatible reaction conditions are unavoidable challenges in a single operation. To address these two issues, we develop a supported dual catalysts system to overcome these conflicts from incompatibility to compatibility, resulting in an efficient one-pot redox deracemization of secondary alcohols. During this transformation, the TEMPO species onto the outer surface of silica nanoparticles catalyze the oxidation of racemic alcohols to ketones, and the chiral Rh/diamine species in the nanochannels of the thermoresponsive polymer-coated hollow-shell mesoporous silica enable the asymmetric transfer hydrogenation (ATH) of ketones to chiral alcohols. To demonstrate the general feasibility, a series of orthogonal oxidation/ATH cascade reactions are compared to prove the compatible benefits in the elimination of their deactivations and the balance of the cascade directionality. As presented in this study, this redox deracemization process provides various chiral alcohols with enhanced yields and enantioselectivities relative to those from unsupported dual catalysts systems. Furthermore, the dual catalysts can be recycled continuously, making them an attractive feature in the application.
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.
Palladium-Catalyzed Regioselective and Diastereoselective C-Glycosylation by Allyl-Allyl Coupling
Li, Junhao,Zheng, Nan,Duan, Xuelun,Li, Rui,Song, Wangze
supporting information, p. 846 - 850 (2020/12/13)
A Pd-catalyzed C-glycosylation reaction was developed by allyl-allyl coupling process using Achmatowicz rearrangement products as donors and methylcoumarins as acceptors under mild conditions. This method featured regio- and diastereoselectivities, stereo
Arene-Immobilized Ru(II)/TsDPEN Complexes: Synthesis and Applications to the Asymmetric Transfer Hydrogenation of Ketones
Doherty, Simon,Knight, Julian G.,Alshaikh, Hind,Wilson, James,Waddell, Paul G.,Wills, Corinne,Dixon, Casey M.
supporting information, p. 226 - 235 (2020/12/31)
The Noyori-Ikariya (arene)Ru(II)/TsDPEN precatalyst has been anchored to amorphous silica and DAVISIL through the η6-coordinated arene ligand via a straightforward synthesis and the derived systems, (arene)Ru(II)/TsDPEN@silica and (arene)Ru(II)/TsDPEN@DAVISIL, form highly efficient catalysts for the asymmetric transfer hydrogenation of a range of electron-rich and electron-poor aromatic ketones, giving good conversion and excellent ee's under mild reaction conditions. Moreover, catalyst generated in situ immediately prior to addition of substrate and hydrogen donor, by reaction of silica-supported [(arene)RuCl2]2 with (S,S)-TsDPEN, was as efficient as that generated from its preformed counterpart [(arene)Ru{(S,S)-TsDPEN}Cl]@silica. Gratifyingly, the initial TOFs (up to 1085 h?1) and ee's (96–97 %) obtained with these catalysts either rivalled or outperformed those previously reported for catalysts supported by either silica or polymer immobilized through one of the nitrogen atoms of TsDPEN. While the high ee's were also maintained during recycle studies, the conversion dropped steadily over the first three runs due to gradual leaching of the ruthenium.
Abiotic reduction of ketones with silanes catalysed by carbonic anhydrase through an enzymatic zinc hydride
Ji, Pengfei,Park, Jeeyoung,Gu, Yang,Clark, Douglas S.,Hartwig, John F.
, p. 312 - 318 (2021/02/26)
Enzymatic reactions through mononuclear metal hydrides are unknown in nature, despite the prevalence of such intermediates in the reactions of synthetic transition-metal catalysts. If metalloenzymes could react through abiotic intermediates like these, then the scope of enzyme-catalysed reactions would expand. Here we show that zinc-containing carbonic anhydrase enzymes catalyse hydride transfers from silanes to ketones with high enantioselectivity. We report mechanistic data providing strong evidence that the process involves a mononuclear zinc hydride. This work shows that abiotic silanes can act as reducing equivalents in an enzyme-catalysed process and that monomeric hydrides of electropositive metals, which are typically unstable in protic environments, can be catalytic intermediates in enzymatic processes. Overall, this work bridges a gap between the types of transformation in molecular catalysis and biocatalysis. [Figure not available: see fulltext.]
Synthetic Studies toward the Berkeleyacetal Core Architecture
Márquez-Cadena, Miguel Adrián,Zhang, Wei,Tong, Rongbiao
supporting information, p. 9227 - 9231 (2021/11/30)
Berkeleyacetals are structurally complex natural products that have shown potent anti-inflammatory activity. The presence of a highly dense oxygen functionality and a polycyclic ring system presents significant synthetic challenges. Herein, we report an e
Chiral amino-pyridine-phosphine tridentate ligand, manganese complex, and preparation method and application thereof
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Paragraph 0597-0600; 0602, (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.
A simple and efficient asymmetric hydrogenation of heteroaromatic ketones with iridium catalyst composed of chiral diamines and achiral phosphines
Li, Chun,Lu, Xunhua,Wang, Mengna,Zhang, Ling,Jiang, Jian,Yan, Shunfa,Yang, Yuanyong,Zhao, Yonglong,Zhang, Lin
, (2020/09/02)
An efficient iridium catalyst composed of a simple and commercially available o-methoxytriphenylphosphine and 9-Amino (9-deoxy) epi-cinchonine was applied to the asymmetric hydrogenation of heteroaromatic ketones. A range of simple heteroaromatic ketones could be hydrogenated with good to excellent enantioselectivities and high activities. In particular, thiophene ketones and furyl ketones furnished 98.6% ee with up to 2.18 × 104(1/h) TOF. This catalytic system can be of practical value.
