6946-35-6Relevant articles and documents
Catalytic Activity of Quaternary Ammonium Poly(methylstyrene-co-styrene) Resin in an Organic Solvent/Alkaline Solution
Wu, Ho-Shing,Lee, Chun-Shen
, p. 217 - 223 (2001)
The reaction of 4-methoxyphenylacetic acid with n-bromobutane using triphase catalysis in a dichloromethane/alkaline solution was investigated. Meanwhile, the lab-produced resins and the commercial ion-exchange resin (triphase catalyst) were characterized in terms of the density of active sites, thermal stability, imbibed solvent composition, and reuse of the resin. The amount of active sites in the resin was characterized by EA, TGA, and Volhard methods. The imbibed amounts of organic solvent and water and the volume ratios for lab-produced resins were larger than those for commercial resins. The degradation of the catalyst due to temperature is greater than that due to base concentration.
Mechanistic insight into the synergistic Cu/Pd-catalyzed carbonylation of aryl iodides using alcohols and dioxygen as the carbonyl source
Li, Junxuan,Zhou, Jinlei,Wang, Yumei,Yu, Yue,Liu, Qiang,Yang, Tilong,Chen, Huoji,Cao, Hua
, p. 68 - 74 (2021/11/16)
Pd-catalyzed carbonylation, as an efficient synthetic approach to the installation of carbonyl groups in organic compounds, has been one of the most important research fields in the past decade. Although elegant reactions that allow highly selective carbonylations have been developed, straightforward routes with improved reaction activity and broader substrate scope remain long-term challenges for new practical applications. Here, we show a new type of synergistic Cu/Pd-catalyzed carbonylation reaction using alcohols and dioxgen as the carbonyl sources. A broad range of aryl iodides and alcohols are compatible with this protocol. The reaction is concise and practical due to the ready availability of the starting materials and the scalability of the reaction. In addition, the reaction affords lactones and lactams in an intermolecular fashion. Moreover, DFT calculations have been performed to study the detailed mechanisms. [Figure not available: see fulltext.]
Encapsulation of heteropolyacids within hollow microporous polymer nanospheres for sustainable esterification reaction
He, Zhiwei,Huang, Kun,Song, Chunmei,Wang, Huaqing,Yu, Haitao,Zhang, Li
, (2021/10/25)
Herein, the Keggin structural phosphotungstic acid (HPW) has been successfully encapsulated within hollow microporous polymer nanospheres (H-MPNs) by a “ship-in-bottle” approach. The H-MPNs are formed by self-assembly induced by hyper-crosslinking of polylactide-b-polystyrene (PLA-b-PS). The obtained catalysts (HPW@H-MPNs) exhibit more sustainable availability than the previously reported HPW-supported catalysts in esterification reaction. This excellent sustainability can be attributed to the stable microporous channels in H-MPNs which are smaller than the molecular size of HPW, thereby effectively preventing the HPW from leaking out. Moreover, such catalysts also perform well in terms of catalytic activity and universality because of the combination of a hollow structure in the interior and permeable pore channels in the shells. This type of polymer carrier and general encapsulation method may provide a new strategy for developing more sustainable catalysts for various chemical reactions.
Enolate-Based Regioselective Anti-Beckmann C-C Bond Cleavage of Ketones
Jahn, Ullrich,Ma?ek, Tomá?
, p. 11608 - 11632 (2021/09/02)
The Baeyer-Villiger or Beckmann rearrangements are established methods for the cleavage of ketone derivatives under acidic conditions, proceeding for unsymmetrical precursors selectively at the more substituted site. However, the fragmentation regioselectivity cannot be switched and fragmentation at the less-substituted terminus is so far not possible. We report here that the reaction of ketone enolates with commercial alkyl nitrites provides a direct and regioselective way of fragmenting ketones into esters and oximes or ω-hydroxyimino esters, respectively. A comprehensive study of the scope of this reaction with respect to ketone classes and alkyl nitrites is presented. Control over the site of cleavage is gained through regioselective enolate formation by various bases. Oxidation of kinetic enolates of unsymmetrical ketones leads to the otherwise unavailable "anti-Beckmann"cleavage at the less-substituted side chain, while cleavage of thermodynamic enolates of the same ketones represents an alternative to the Baeyer-Villiger oxidation or the Beckmann rearrangement under basic conditions. The method is suited for the transformation of natural products and enables access to orthogonally reactive dicarbonyl compounds.
Carboxyboronate as a Versatile In Situ CO Surrogate in Palladium-Catalyzed Carbonylative Transformations
Tien, Chieh-Hung,Trofimova, Alina,Holownia, Aleksandra,Kwak, Branden S.,Larson, Reed T.,Yudin, Andrei K.
supporting information, p. 4342 - 4349 (2020/12/25)
The application of carboxy-MIDA-boronate (MIDA=N-methyliminodiacetic acid) as an in situ CO surrogate for various palladium-catalyzed transformations is described. Carboxy-MIDA-boronate was previously shown to be a bench-stable boron-containing building block for the synthesis of borylated heterocycles. The present study demonstrates that, in addition to its utility as a precursor to heterocycle synthesis, carboxy-MIDA-boronate is an excellent in situ CO surrogate that is tolerant of reactive functionalities such as amines, alcohols, and carbon-based nucleophiles. Its wide functional-group compatibility is highlighted in the palladium-catalyzed aminocarbonylation, alkoxycarbonylation, carbonylative Sonogashira coupling, and carbonylative Suzuki–Miyaura coupling of aryl halides. A variety of amides, esters, (hetero)aromatic ynones, and bis(hetero)aryl ketones were synthesized in good-to-excellent yields in a one-pot fashion.
Electro-Oxidative Selective Esterification of Methylarenes and Benzaldehydes
Yu, Congjun,?zkaya, Bünyamin,Patureau, Frederic W.
supporting information, p. 3682 - 3687 (2021/02/01)
A mild and green electro-oxidative protocol to construct aromatic esters from methylarenes and alcohols is herein reported. Importantly, the reaction is free of metals, chemical oxidants, bases, acids, and operates at room temperature. Moreover, the design of the electrolyte was found critical for the oxidation state and structure of the coupling products, a rarely documented effect. This electro-oxidative coupling process also displays exceptional tolerance of many fragile easily oxidized functional groups such as hydroxy, aldehyde, olefin, alkyne, as well as neighboring benzylic positions. The enantiomeric enrichment of some chiral alcohols is moreover preserved during this electro-oxidative coupling reaction, making it overall a promising synthetic tool.
Zr-MOF-808 as Catalyst for Amide Esterification
Villoria-del-álamo, Beatriz,Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
supporting information, p. 4588 - 4598 (2020/12/25)
In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.
IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
Talukdar, Ranadeep
supporting information, p. 5303 - 5308 (2020/04/17)
An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
Nickel-Catalyzed Esterification of Amides Under Mild Conditions
Li, Jun-Fei,Wang, Yao-Fang,Wu, Yuan-Yuan,Liu, Wen-Jing,Wang, Jun-Wen
, p. 874 - 880 (2019/11/13)
Abstract: The use of ligands to adjust the catalytic activity of the catalyst for esterification of amides is challenge in organic chemistry. In this paper, Nickel(II)-NHC-catalyzed the esterification reaction between N,N-di-Boc amide and alcohols at room temperature have been demonstrated. The imidazolium salt bearing a hydroxyl functionalized side arm showed high effective catalytic activity in the activation of the amide N–C bond in air atmosphere. Graphic Abstract: [Figure not available: see fulltext.].
Esterification of Tertiary Amides: Remarkable Additive Effects of Potassium Alkoxides for Generating Hetero Manganese–Potassium Dinuclear Active Species
Akiyama, Shoko,Himo, Fahmi,Hirai, Takahiro,Katayama, Shoichiro,Kato, Daiki,Mai, Binh Khanh,Mashima, Kazushi,Nagae, Haruki
supporting information, (2020/07/25)
A catalyst system of mononuclear manganese precursor 3 combined with potassium alkoxide served as a superior catalyst compared with our previously reported manganese homodinuclear catalyst 2 a for esterification of not only tertiary aryl amides, but also tertiary aliphatic amides. On the basis of stoichiometric reactions of 3 and potassium alkoxide salt, kinetic studies, and density functional theory (DFT) calculations, we clarified a plausible reaction mechanism in which in situ generated manganese–potassium heterodinuclear species cooperatively activates the carbonyl moiety of the amide and the OH moiety of the alcohols. We also revealed details of the reaction mechanism of our previous manganese homodinuclear system 2 a, and we found that the activation free energy (ΔG≠) for the manganese–potassium heterodinuclear complex catalyzed esterification of amides is lower than that for the manganese homodinuclear system, which was consistent with the experimental results. We further applied our catalyst system to deprotect the acetyl moiety of primary and secondary amines.
