scholarly journals The Quest for the Ideal Base: Rational Design of a Nickel Precatalyst Enables Mild, Homogeneous C–N Cross-Coupling

2020 ◽  
Author(s):  
Richard Liu ◽  
Joseph Dennis ◽  
Stephen L. Buchwald
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Heterogeneous Reaction ◽  
Cross Coupling ◽  
Ni Catalyst ◽  
Palladium Catalyzed ◽  
Aryl Amines ◽  
Bidentate Phosphine ◽  
Bidentate Phosphine Ligand ◽  
The Many

Palladium-catalyzed amination reactions using soluble organic bases have provided a solution to the many issues associated with heterogeneous reaction conditions. Still, homogeneous C–N cross-coupling approaches cannot yet employ bases as weak and economical as trialkylamines. Furthermore, organic base-mediated methods have not been developed for Ni(0/II) catalysis, despite some advantages of such systems over analogous Pd-based catalysts. We designed a new air-stable and easily prepared Ni(II) precatalyst bearing an electron-deficient bidentate phosphine ligand that enables the cross-coupling of aryl triflates with aryl amines using triethylamine (TEA) as base. The method is tolerant of sterically-congested coupling partners, as well as those bearing base- and nucleophile-sensitive functional groups. With the aid of density functional theory (DFT) calculations, we determined that the electron-deficient auxiliary ligands decrease both the pKa of the Ni-bound amine and the barrier to reductive elimination from the resultant Ni(II)–amido complex. Moreover, we determined that precluding Lewis acid-base complexation between the Ni catalyst and the base, due to steric factors, is important for avoiding catalyst inhibition.

scholarly journals The Quest for the Ideal Base: Rational Design of a Nickel Precatalyst Enables Mild, Homogeneous C–N Cross-Coupling

2020 ◽  
Author(s):  
Richard Liu ◽  
Joseph Dennis ◽  
Stephen L. Buchwald
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Heterogeneous Reaction ◽  
Cross Coupling ◽  
Ni Catalyst ◽  
Palladium Catalyzed ◽  
Aryl Amines ◽  
Bidentate Phosphine ◽  
Bidentate Phosphine Ligand ◽  
The Many

Palladium-catalyzed amination reactions using soluble organic bases have provided a solution to the many issues associated with heterogeneous reaction conditions. Still, homogeneous C–N cross-coupling approaches cannot yet employ bases as weak and economical as trialkylamines. Furthermore, organic base-mediated methods have not been developed for Ni(0/II) catalysis, despite some advantages of such systems over analogous Pd-based catalysts. We designed a new air-stable and easily prepared Ni(II) precatalyst bearing an electron-deficient bidentate phosphine ligand that enables the cross-coupling of aryl triflates with aryl amines using triethylamine (TEA) as base. The method is tolerant of sterically-congested coupling partners, as well as those bearing base- and nucleophile-sensitive functional groups. With the aid of density functional theory (DFT) calculations, we determined that the electron-deficient auxiliary ligands decrease both the pKa of the Ni-bound amine and the barrier to reductive elimination from the resultant Ni(II)–amido complex. Moreover, we determined that precluding Lewis acid-base complexation between the Ni catalyst and the base, due to steric factors, is important for avoiding catalyst inhibition.

Direct synthesis of adipic acid esters via palladium-catalyzed carbonylation of 1,3-dienes

Science ◽  
2019 ◽  
Vol 366 (6472) ◽  
pp. 1514-1517 ◽  
Author(s):  
Ji Yang ◽  
Jiawang Liu ◽  
Helfried Neumann ◽  
Robert Franke ◽  
Ralf Jackstell ◽  
...  
Keyword(s):  
Adipic Acid ◽  
Direct Synthesis ◽  
Reaction Network ◽  
Catalyst System ◽  
Environmentally Benign ◽  
Palladium Catalyzed ◽  
Bidentate Phosphine ◽  
Cost Efficient ◽  
Bidentate Phosphine Ligand ◽  
Acid Esters

The direct carbonylation of 1,3-butadiene offers the potential for a more cost-efficient and environmentally benign route to industrially important adipic acid derivatives. However, owing to the complex reaction network of regioisomeric carbonylation and isomerization pathways, a selective practical catalyst for this process has thus far proven elusive. Here, we report the design of a pyridyl-substituted bidentate phosphine ligand (HeMaRaphos) that, upon coordination to palladium, catalyzes adipate diester formation from 1,3-butadiene, carbon monoxide, and butanol with 97% selectivity and 100% atom-economy under industrially viable and scalable conditions (turnover number > 60,000). This catalyst system also affords access to a variety of other di- and triesters from 1,2- and 1,3-dienes.

A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes

Synthesis ◽  
2021 ◽  
Author(s):  
Mingzhong Cai ◽  
Shengyong You ◽  
Rongli Zhang
Keyword(s):  
Magnetic Field ◽  
Formic Acid ◽  
Aromatic Aldehydes ◽  
Aryl Iodides ◽  
Apparent Loss ◽  
Palladium Catalyzed ◽  
Bidentate Phosphine ◽  
Bidentate Phosphine Ligand ◽  
Modified Magnetic Nanoparticles ◽  
Co Gas

AbstractA magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored­ palladium(II) complex [2P-Fe3O4@SiO2-Pd(OAc)2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh3 as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.

Anchored Pd(0) Nanoparticles on Synthetic Talc for the Synthesis of Biaryls and a Precursor of Angiotensin II Inhibitors

Synthesis ◽  
2020 ◽  
Author(s):  
Nelson Luís C. Domingues ◽  
Beatriz F. dos Santos ◽  
Beatriz A. L. da Silva ◽  
Aline R. de Oliveira ◽  
Maria H. Sarragiotto
Keyword(s):  
Angiotensin Ii ◽  
Palladium Catalysts ◽  
Rational Design ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Cost Effective ◽  
Significant Loss ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Short Time

AbstractThe palladium-catalyzed Suzuki–Miyaura cross-coupling reaction is one of the most important and efficient reactions to prepare a variety of organic compounds, including biaryls. Despite the overwhelming number of reports related to this topic, some methodological difficulties persist in terms of catalyst handling, recovery, and reuse, as well as the reaction media. This work reports the rational design of new, efficient, cost-effective, and reusable palladium catalysts supported on synthetic talc for the Suzuki–Miyaura reaction. From the results, key points were identified: both designed catalysts accelerated the reaction in EtOH and an open-flask setup, affording moderate to excellent yields within a short time (e.g., 30 min) even for deactivated aryl halides; the protocol can be applied to a great number of both cross-coupling partners, showing an excellent functional group tolerance; the catalysts can be recovered and reused without significant loss of activity. This protocol was used for the synthesis of a precursor of angiotensin II inhibitors such as valsartan, losartan, irbesartan, and telmisartan.

Biphasic Aqueous Reaction Conditions for Process-Friendly Palladium-Catalyzed C–N Cross-Coupling of Aryl Amines

2019 ◽  
Vol 23 (8) ◽  
pp. 1752-1757 ◽  
Author(s):  
Subhash Pithani ◽  
Marcus Malmgren ◽  
Carl-Johan Aurell ◽  
Grigorios Nikitidis ◽  
Stig D. Friis
Keyword(s):  
Cross Coupling ◽  
Reaction Conditions ◽  
Palladium Catalyzed ◽  
Aryl Amines

Mechanism, Reactivity, and Selectivity in Palladium-Catalyzed Organosilicon-Based Cross Coupling Reaction

2021 ◽  
Author(s):  
Qian Wang ◽  
Hui-Mei Jiang ◽  
Shuping Zhuo ◽  
Li-Ping Xu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Dft Study ◽  
Functional Theory ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Strain Release

A comprehensive density functional theory (DFT) study has been performed to elucidate the mechanistic details of the Pd-catalyzed strain-release organosilicon based cross coupling reaction of four- and five-membered silacycles. The...

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