74982-51-7Relevant academic research and scientific papers
Synthesis of a Class of Chiral-Bridged Phosphoramidite Ligands and Their Applications in the First Iridium-Catalyzed Asymmetric Addition of Arylboronic Acids to Isatins
Zhuang, Yue,He, Yuwei,Zhou, Zihong,Xia, Wang,Cheng, Chuyu,Wang, Meng,Chen, Bin,Zhou, Zhongyuan,Pang, Jiyan,Qiu, Liqin
, p. 6968 - 6975 (2015)
A series of novel chiral phosphoramidite ligands based on chiral-bridged biphenyl backbones have been prepared conveniently and characterized. The ligands complexed with [IrCodCl]2 provided the first iridium catalyst system for the asymmetric a
The Importance of 1,5-Oxygen???Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis
Cockroft, Scott L.,Elmi, Alex,Frost, Aileen B.,Ling, Kenneth B.,McLaughlin, Calum,Morris, Rylie K.,Pascoe, Dominic J.,Slawin, Alexandra M. Z.,Smith, Andrew D.,Smith, Terry K.,Willoughby, Patrick H.,Woods, Andrew M.,Young, Claire M.,de la Houpliere, Alix
, p. 3705 - 3710 (2020/02/11)
The importance of 1,5-O???chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O???Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions. A gram-scale synthesis of the most active selenium analogue was developed using a previously unreported seleno-Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N-acylated intermediates.
Copper-Catalyzed Asymmetric Propargylic Alkylation with Oxindoles: Diastereo- A nd Enantioselective Construction of Vicinal Tertiary and All-Carbon Quaternary Stereocenters
Xia, Jin-Tao,Hu, Xiang-Ping
, p. 1102 - 1107 (2020/02/15)
A copper-catalyzed asymmetric propargylic alkylation of propargylic acetates with 3-substituted oxindoles for the stereoselective construction of vicinal tertiary and all-carbon quaternary stereocenters in a 3,3-disubstituted oxindole skeleton has been realized. The reaction proceeded smoothly under the catalysis of Cu(MeCN)4PF6combined with a chiral tridentate ferrocenyl P,N,N ligand, leading to a broad range of optically active 3,3-disubstituted oxindoles in high yields and with excellent diastereo- A nd enantioselectivities.
A C=O???Isothiouronium Interaction Dictates Enantiodiscrimination in Acylative Kinetic Resolutions of Tertiary Heterocyclic Alcohols
Greenhalgh, Mark D.,Smith, Samuel M.,Walden, Daniel M.,Taylor, James E.,Brice, Zamira,Robinson, Emily R. T.,Fallan, Charlene,Cordes, David B.,Slawin, Alexandra M. Z.,Richardson, H. Camille,Grove, Markas A.,Cheong, Paul Ha-Yeon,Smith, Andrew D.
, p. 3200 - 3206 (2018/02/22)
A combination of experimental and computational studies have identified a C=O???isothiouronium interaction as key to efficient enantiodiscrimination in the kinetic resolution of tertiary heterocyclic alcohols bearing up to three potential recognition motifs at the stereogenic tertiary carbinol center. This discrimination was exploited in the isothiourea-catalyzed acylative kinetic resolution of tertiary heterocyclic alcohols (38 examples, s factors up to >200). The reaction proceeds at low catalyst loadings (generally 1 mol %) with either isobutyric or acetic anhydride as the acylating agent under mild conditions.
A kind of phosphoramidite ligand and its preparation method and application
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Paragraph 0117-0119; 0132; 0133, (2018/04/21)
The invention relates to the field of chemical catalysis and discloses a phosphoramidite ligand as well as a preparation method and an application thereof. The synthesized phosphoramidite ligand and an enantiomer or a racemate of the phosphoramidite ligand take biphenyl as a framework and are subjected to an asymmetric induced reaction of axial chirality to realize complete transfer from central chirality to axial chirality. A synthetic method for the phosphoramidite ligand and the enantiomer or the racemate of the phosphoramidite ligand is simple and economic, and a common and complex chiral resolution process is avoided during chiral ligand preparation. The phosphoramidite ligand and the enantiomer or the racemate of the phosphoramidite ligand is employed to form the ligand together with active metal-iridium for catalyzing an asymmetric addition reaction of N-protected isatin and arylboronic acid, a very good catalytic effect is achieved, and a product can obtain the yield of more than 96% and the enantiomeric excess (ee) value of more than 92%.
Nickel(II)-catalyzed addition reaction of arylboronic acids to isatins
Zhang, Yu-Yang,Chen, Huixuan,Jiang, Xiaoding,Liang, Hao,He, Xuefeng,Zhang, Yaqi,Chen, Xiangmeng,He, Wenhuan,Li, Yongsu,Qiu, Liqin
, p. 2245 - 2250 (2018/04/02)
A Ni-catalyzed addition of arylboronic acids to isatins was first developed. The reaction, driven by Ni(acac)2 and dppp as the phosphine ligand, gave 3-aryl-3-hydroxy-2-oxindoles in up to 97% yield. Scopes of benzyl-protected isatins and arylboronic acids were examined. Substituted phenylboronic acids along with fused-ring and heterocyclic boronic acids reacted with isatins smoothly. Preliminary asymmetric catalysis was investigated as well, showing moderate enantioselectivity. The mechanism was also described.
Employing Arynes for the Generation of Aryl Anion Equivalents and Subsequent Reaction with Aldehydes
Gaykar, Rahul N.,Bhunia, Anup,Biju, Akkattu T.
, p. 11333 - 11340 (2018/07/21)
Arynes are highly reactive intermediates, which are utilized for the electrophilic arylation of various X-H bonds (X = O, N, S etc.). Herein, a new synthetic strategy is demonstrated, where arynes are converted into aryl anion equivalents by treatment with phosphines and a base. The addition of phosphines to arynes form the phosphonium salts, which in the presence of a carbonate base generates the aryl anion equivalent. Subsequent addition of the aryl anions with aldehydes afforded the secondary alcohols.
Metal-free base-mediated oxidative annulation cascades to 3-substituted-3-hydroxyoxindole and its 3-spirocyclic derivative
Liu, Min,Zhang, Chunxia,Ding, Mingruo,Tang, Bencan,Zhang, Fengzhi
supporting information, p. 4509 - 4514 (2017/10/13)
A simple and efficient method was developed for the construction of the medicinally important 3-substituted-3-hydroxyoxindole and its 3-spirocyclic derivatives with readily available aniline derivatives as starting materials. This highly atom- and step-economical one-pot protocol was carried out under metal-free base-mediated conditions through a novel oxidative annulation strategy with oxygen as the oxidant. The key intermediates were isolated and confirmed. A reasonable reaction pathway was proposed and supported by the preliminary experiments, and the computational studies were carried out to understand the energetics of the key rearrangement reaction.
Schwartz's Reagent-Mediated Regiospecific Synthesis of 2,3-Disubstituted Indoles from Isatins
Ulikowski,Furman
supporting information, p. 149 - 151 (2016/02/03)
An expeditious, functional group-tolerant synthesis of indoles from isatins is described. Isatins are treated with Grignard reagents to yield oxindoles. These, in turn, are reduced with Schwartz's reagent and subjected to nucleophile addition and dehydrat
Axial tri-tert-butylphosphane coordination to Rh2(OAc)4: Synthesis, structure, and catalytic studies
Tan, Jiantao,Kuang, Yi,Wang, Yi,Huang, Qingfei,Zhu, Jin,Wang, Yuanhua
supporting information, p. 3139 - 3147 (2016/10/09)
The introduction of strong σ-donor axial ligands to the Rh-Rh metal bond has been utilized as an effective way to provide new chemical reactivities to bimetallic dirhodium(II) complexes. In this report, Rh2(OAc)4 complexes with axial
