40150-91-2Relevant academic research and scientific papers
Catalytic α-Deracemization of Ketones Enabled by Photoredox Deprotonation and Enantioselective Protonation
Chen, Shuming,Gao, Anthony Z.,Ivlev, Sergei I.,Meggers, Eric,Nie, Xin,Ye, Chen-Xi,Zhang, Chenhao
supporting information, p. 13393 - 13400 (2021/09/03)
This study reports the catalytic deracemization of ketones bearing stereocenters in the α-position in a single reaction via deprotonation, followed by enantioselective protonation. The principle of microscopic reversibility, which has previously rendered this strategy elusive, is overcome by a photoredox deprotonation through single electron transfer and subsequent hydrogen atom transfer (HAT). Specifically, the irradiation of racemic pyridylketones in the presence of a single photocatalyst and a tertiary amine provides nonracemic carbonyl compounds with up to 97% enantiomeric excess. The photocatalyst harvests the visible light, induces the redox process, and is responsible for the asymmetric induction, while the amine serves as a single electron donor, HAT reagent, and proton source. This conceptually simple light-driven strategy of coupling a photoredox deprotonation with a stereocontrolled protonation, in conjunction with an enrichment process, serves as a blueprint for other deracemizations of ubiquitous carbonyl compounds.
Method for synthesizing aryl propionic acid by metal-free catalysis of carbon dioxide carboxylation
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Paragraph 0048-0064, (2021/02/10)
The invention relates to the field of carbon dioxide immobilization and conversion, and particularly discloses a method for synthesizing aryl propionic acid by metal-free catalysis of carbon dioxide carboxylation. The method comprises the following steps: stirring a mixed solution of a diselenide catalyst and a styrene compound in a carbon dioxide atmosphere, adding hydrogen peroxide, and stirringto react, thereby obtaining the aryl propionic acid. Styrene is directly used as a raw material, diselenide is used as a catalyst to realize a carboxylation reaction of olefin and carbon dioxide, andcompared with metal catalyst residues or halogen-containing byproducts in a traditional synthesis method, the byproducts in the method only contain water, and small molecular diselenide is used as the catalyst to replace the traditional metal catalyst, and metal residuals are avoided.
Preparation method of organic carboxylic acid
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Paragraph 0077-0079, (2019/10/15)
The invention discloses a preparation method of organic carboxylic acid. The preparation method comprises the following steps that catalysts, olefins, water and solvents are added into a reaction container; CO is introduced; heating reaction is performed; after the reaction completion, separation is performed to obtain organic carboxylic acid; the catalysts comprise transition metal catalysts, ligands and catalysis assistants; the catalysis assistants comprise Lewis acid salt. The preparation method has the advantages that the dependency on protonic acid in the prior art is avoided; the Lewisacid salt is used as the catalysis assistant, so that the corrosion of a reaction system on equipment can be effectively prevented; the requirements on equipment are lowered. The preparation method has excellent substrate practicability; the operation steps are simple and fast; the reaction conditions are mild and are easy to control; the raw materials are cheap and can be easily obtained; the product yield and the product purity are high; the preparation method is suitable for large-scale industrial production; the normal/iso ratio of reaction products can be regulated and controlled throughthe catalysis assistants; the defects of regulating and controlling the normal/iso ratio of the reaction products by traditional phosphine ligands are overcome; the reaction progress of the reaction is simplified; the cost is favorably reduced.
Regioselectivity inversion tuned by iron(iii) salts in palladium-catalyzed carbonylations
Huang, Zijun,Cheng, Yazhe,Chen, Xipeng,Wang, Hui-Fang,Du, Chen-Xia,Li, Yuehui
supporting information, p. 3967 - 3970 (2018/04/23)
Impactful regioselectivity control is crucial for cost-effective chemical synthesis. By using cheap and abundant iron(iii) salts, the hydroxycarbonylations of both aromatic and aliphatic alkenes were significantly enhanced in both reactivity and selectivity (iso/n or n/iso up to >99:1). Moreover, Pd-catalyzed carbonylation selectivity can be switched from branched to linear by using different Fe(iii) salts. In addition, similar results were obtained for the carbonylation of secondary alcohols.
Ligand-Controlled Regioselective Hydrocarboxylation of Styrenes with CO2 by Combining Visible Light and Nickel Catalysis
Meng, Qing-Yuan,Wang, Shun,Huff, Gregory S.,Konig, Burkhard
supporting information, p. 3198 - 3201 (2018/03/13)
The ligand-controlled Markovnikov and anti-Markovnikov hydrocarboxylation of styrenes with atmospheric pressure of CO2 at room temperature using dual visible-light-nickel catalysis has been developed. In the presence of neocuproine as ligand, the Markovnikov product is obtained exclusively, while employing 1,4-bis(diphenylphosphino)butane (dppb) as the ligand favors the formation of the anti-Markovnikov product. A range of functional groups and electron-poor, -neutral, as well as electron-rich styrene derivatives are tolerated by the reaction, providing the desired products in moderate to good yields. Preliminary mechanistic investigations indicate the generation of a nickel hydride (H-NiII) intermediate, which subsequently adds irreversibly to styrenes.
A Ligand-Directed Catalytic Regioselective Hydrocarboxylation of Aryl Olefins with Pd and Formic Acid
Liu, Wei,Ren, Wenlong,Li, Jingfu,Shi, Yuan,Chang, Wenju,Shi, Yian
supporting information, p. 1748 - 1751 (2017/04/11)
An effective Pd-catalyzed hydrocarboxylation of aryl olefins with Ac2O and formic acid is described. A variety of 2- and 3-arylpropanoic acids can be regioselectively formed by the judicious choice of ligand without the use of toxic CO gas.
Cp2TiCl2-Catalyzed Regioselective Hydrocarboxylation of Alkenes with CO2
Shao, Peng,Wang, Sheng,Chen, Chao,Xi, Chanjuan
supporting information, p. 2050 - 2053 (2016/06/01)
Cp2TiCl2-catalyzed regioselective hydrocarboxylation of alkenes with CO2 to give carboxylic acids in high yields has been developed in the presence of iPrMgCl. The reaction proceeds with a wide range of alkenes under mild conditions. Styrene and its derivatives can transform to α-aryl carboxylic acids, and aliphatic alkenes can transform to form alkanoic acids.
Hydrocarboxylation of olefins by supported aqueous-phase catalysis
He, Zhenhong,Hou, Zhenshan,Zhang, Yagang,Wang, Tianfu,Dilixiati, Yierxiati,Eli, Wumanjiang
, p. 147 - 154 (2015/03/30)
Pd-TPPTS complexes supported on acidic macro-porous resins (Pd-TPPTS/resin) have been employed for the hydrocarboxylation of 1-hexene and styrene derivatives by supported aqueous phase catalysis (SAPC). Acidic macroporous resins acted as substitutes for both heterogeneous acids and supports of Pd-TPPTS complexes afforded many advantages, such as easy separation from organic products and good reusability. The prepared Pd-TPPTS/resin catalysts were characterized by FT-IR, TG, SEM and N2 physisorption, which demonstrated that the Pd-TPPTS complexes were loaded on the resin. Compared with homogeneous analogue, the present SAP catalyst offered higher total acid yield and selectivity towards linear acid in the hydrocarboxylation of 1-hexene. Moreover, it was found that water had a significant influence on the catalytic activity and selectivity toward linear acid over the SAP catalyst. Optimum water/resin ratio at about 66.7% in the SAP catalyst afforded maximum activity under the given reaction temperature. The present SAP catalyst was highly Pd-leaching resistant and can be reused at least four times without obvious loss in activity.
Anchored Pd-complexes in mesoporous supports: Synthesis, characterization and catalysis studies for carbonylation reactions
Sarkar, Bibhas R.,Chaudhari, Raghunath V.
, p. 154 - 173 (2013/01/15)
Pd(pyca)(PPh3)(OTs) [pyca = 2-picolinate] complex is efficiently anchored inside different mesoporous matrices, such as MCM-41, MCM-48, SBA-15 using a molecular aminopropyl tether moiety employing different synthesis strategies. Thorough characterization of the materials using powder XRD, multinuclear (13C, 29Si, 31P) CP-MAS NMR, XPS, SEM, N2-sorption studies etc. confirmed the successful anchoring of the palladium complex to the walls of the support matrices thus establishing the synthesis protocols unambiguously. The catalysts were found to be highly active and selective for the carbonylation of different aryl olefins and alcohols. Consecutive recycling and successful reuse proved the stability and true heterogeneous nature of all the anchored catalysts, which is a substantial advancement over the existing heterogeneous catalysts for carbonylation.
Iron-catalyzed, highly regioselective synthesis of α-aryl carboxylic acids from styrene derivatives and CO2
Greenhalgh, Mark D.,Thomas, Stephen P.
supporting information; experimental part, p. 11900 - 11903 (2012/09/07)
The iron-catalyzed hydrocarboxylation of aryl alkenes has been developed using a highly active bench-stable iron(II) precatalyst to give α-aryl carboxylic acids in excellent yields and with near-perfect regioselectivity. Using just 1 mol % FeCl2, bis(imino)pyridine 6 (1 mol %), CO 2 (atmospheric pressure), and a hydride source (EtMgBr, 1.2 equiv), a range of sterically and electronically differentiated aryl alkenes were transformed to the corresponding α-aryl carboxylic acids (up to 96% isolated yield). The catalyst was found to be equally active with a loading of 0.1 mol %. Preliminary mechanistic investigations show that an iron-catalyzed hydrometalation is followed by transmetalation and reaction with the electrophile (CO2).
