46181-30-0Relevant articles and documents
C-H and O2Activation at a Pt(II) Center enabled by a novel sulfonated CNN pincer ligand
Watts, David,Wang, Daoyong,Adelberg, Mackenzie,Zavalij, Peter Y.,Vedernikov, Andrei N.
, p. 207 - 219 (2017)
A novel sulfonated CNN pincer ligand has been designed to support CH and O2 activation at a Pt(II) center. The derived cycloplatinated aqua complex 7 was found to be one of the most active reported homogeneous Pt catalysts for H/D exchange between studied arenes (benzene, benzene-d6, toluene-d8, p-xylene, and mesitylene) and 2,2,2-trifluoroethanol (TFE) or 2,2,2- trifluoroethanol-d; the TON for C6D6 as a substrate is >250 after 48 h at 80 °C. The reaction is very selective; no benzylic CH bond activation was observed. The per-CH-bond reactivity diminishes in the series benzene (19) > toluene (p-CH:m-CH:o-CH = 1:0.9:0.2) > xylene (2.9) > mesitylene (1.1). The complex 7 reacts slowly in TFE solutions under ambient light but not in the dark with O2 to selectively produce a Pt(IV) trifluoroethoxo derivative. The H/D exchange reaction kinetics and results of the DFT study suggest that complex 7, and not its TFE derivatives, is the major species responsible for the arene CH bond activation. The reaction deuterium kinetic isotope effect, kH/kD = 1.7, the reaction selectivity, and reaction kinetics modeling suggest that the CH bond cleavage step is rate-determining.
Borenium-Catalyzed Reduction of Pyridines through the Combined Action of Hydrogen and Hydrosilane
Clarke, Joshua J.,Maekawa, Yuuki,Nambo, Masakazu,Crudden, Cathleen M.
supporting information, p. 6617 - 6621 (2021/09/02)
Mesoionic carbene-stabilized borenium ions efficiently reduce substituted pyridines to piperidines in the presence of a hydrosilane and a hydrogen atmosphere. Control experiments and deuterium labeling studies demonstrate reversible hydrosilylation of the pyridine, enabling full reduction of the N-heterocycle under milder conditions. The silane is a critical reaction component to prevent adduct formation between the piperidine product and the borenium catalyst.
Bathocuproine-Enabled Nickel-Catalyzed Selective Ullmann Cross-Coupling of Two sp 2-Hybridized Organohalides
Li, Yuqiang,Yin, Guoyin
supporting information, p. 1657 - 1661 (2021/09/13)
Cross-coupling reactions are essential for the synthesis of complex organic molecules. Here, we report a nickel-catalyzed Ullmann cross-coupling of two sp 2-hybridized organohalides, featuring high cross-selectivity when the two coupling partners are used in a 1:1 ratio. The high chemoselectivity is governed by the bathocuproine ligand. Moreover, the mild reductive reaction conditions allow that a wide range of functional groups are compatible in this Ullmann cross-coupling.
Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant
Wu, Ke,Ling, Yichen,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
supporting information, p. 2273 - 2276 (2021/03/09)
A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.
Sustainable synthesis of quinolines (pyridines) catalyzed by a cheap metal Mn(I)-NN complex catalyst
Chai, Huining,Tan, Weiqiang,Lu, Yuanyuan,Zhang, Guangyao,Ma, Jiping
, (2020/05/22)
This study represents the first example of a bidentate phosphine-free manganese(I)-NN complex catalyst for the synthesis of quinolines (pyridines) through acceptorless dehydrogenative condensation of various secondary alcohols with amino alcohols. The coupling reactions occurred at 3 mol% catalyst loading and 110°C, and tolerated diverse functional groups. Moderate to excellent yields ranging from 45% to 89% were achieved after 12 hr of reaction. The present protocol provides a concise and environmentally friendly method for the construction of heterocyclic compounds.
Synthesis of Pyridines, Quinolines, and Pyrimidines via Acceptorless Dehydrogenative Coupling Catalyzed by a Simple Bidentate P^ N Ligand Supported Ru Complex
Mondal, Rajarshi,Herbert, David E.
supporting information, p. 1310 - 1317 (2020/04/15)
A ruthenium hydrido chloride complex (1) supported by a simple, heteroleptic bidentate P^N ligand (L1) containing a diarylphosphine and a benzannulated phenanthridine donor arm is reported. In the presence of base, complex 1 catalyzes multicomponent reactions using alcohol precursors to produce structurally diverse molecules including pyridines, quinolines, and pyrimidines via acceptorless dehydrogenative coupling pathways. Notably, L1 does not bear readily (de)protonated Br?nsted acidic or basic groups common to transition metal catalysts capable of these sorts of transformations, suggesting metal-ligand cooperativity does not play a significant role in the catalytic reactivity of 1. A rare example of an η2-aldehyde adduct of ruthenium was isolated and structurally characterized, and its role in acceptorless dehydrogenative coupling reactions is discussed.
Meta-dehydrogenative alkylation of arenes with ethers, ketones, and esters catalyzed by ruthenium
Li, Gang,Gao, Yuan,Jia, Chunqi,Wang, Shichong,Yan, Bingxu,Fang, Yu,Yang, Suling
supporting information, p. 8758 - 8763 (2020/12/02)
A meta-dehydrogenative alkylation of arenes with cyclic ethers, ketones, and esters catalyzed by ruthenium is achieved in the presence of a di-tert-butyl peroxide (DTBP) oxidant. Interestingly, when quinoline and isoquinoline are employed as the directing group, or a chain ether as alkylation reagent, the system produces Minisci reaction products. Mechanistic study indicates that meta-dehydrogenative alkylation is a radical process initiated by DTBP with the assistance of a CAr-Ru bond ortho/para-directing effect.
A ortho position alkylation method of organic compound containg pyridine
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Paragraph 0074-0084; 0108-0119, (2020/12/05)
A process for introducing alkyl at ortho positions of organic compounds containing pyridine. The method is not affected by the kind of substituent bonded to the pyridine and can be alkylated with high positional selectivity and high yield at N-based ortho-position of pyridine without being affected by the kind of substituent introduced to pyridine ortho position (pyridine N-based) can be advantageously used for the preparation of a compound containing an alkyl-introduced pyridine structure.
A Highly Efficient Monophosphine Ligand for Parts per Million Levels Pd-Catalyzed Suzuki–Miyaura Coupling of (Hetero)Aryl Chlorides
Choy, Pui Ying,Yuen, On Ying,Leung, Man Pan,Chow, Wing Kin,Kwong, Fuk Yee
, p. 2846 - 2853 (2020/04/09)
A new indolylphosphine WK-phos has been synthesized for Pd-catalyzed Suzuki–Miyaura coupling of (hetero)aryl chlorides with (alkyl)arylboronic acids. Comprising this newly developed ligand with palladium(II) acetate, the resulting catalyst system was found to be highly effective in facilitating the reaction even when the catalyst loading reaches parts per million levels (e.g. 10 ppm). These examples represent one of the lowest catalyst loadings reported to date of employing monophosphine (e.g. Ar-PCy2) for Suzuki–Miyaura reactions. The ligand geometry has also been well-characterized by single-crystal X-ray crystallography.
Palladium-Catalyzed Cascade Reactions of I-Ketonitriles with Arylboronic Acids: Synthesis of Pyridines
Chen, Jiuxi,Hu, Maolin,Li, Renhao,Liu, Jichao,Qi, Linjun,Shao, Yinlin,Yao, Xinrong,Zhao, Zhiwei,Zhen, Qianqian
supporting information, p. 114 - 119 (2020/03/25)
This study presents the first example of the Pd-catalyzed cascade reactions of 5-oxohexanenitrile with arylboronic acids, affording important synthon 2-methylpyridines that can be further translated through C(sp3)-H functionalization to construct pyridine derivatives. Furthermore, this chemistry allows 5-oxo-5-Arylpentanenitrile to react with arylboronic acids to provide unsymmetrical 2,6-diarylpyridines. This protocol paves the way for the practical and atom economical syntheses of valuable pyridines with broad functional groups in moderate to excellent yields under mild conditions.
