scholarly journals Understanding the differences between iron and palladium in cross-coupling reactions

2019 ◽  
Vol 21 (19) ◽  
pp. 9651-9664 ◽  
Author(s):  
Xiaobo Sun ◽  
Marcus V. J. Rocha ◽  
Trevor A. Hamlin ◽  
Jordi Poater ◽  
F. Matthias Bickelhaupt
Keyword(s):  
Quantum Chemical ◽  
Bond Activation ◽  
Cross Coupling ◽  
Design Principles ◽  
Coupling Reactions ◽  
Chemical Analyses ◽  
Cross Coupling Reactions ◽  
Iron Based ◽  
Iron Based Catalysts

We aim at developing design principles, based on quantum chemical analyses, for a novel type of iron-based catalysts that mimic the behavior of their well-known palladium analogs in the bond activation step of cross coupling reactions.

An Iron-Based Catalyst Enables The Enantioconvergent Synthesis of Chiral 1,1-Diarylalkanes Through a Suzuki-Miyaura Cross-Coupling Reaction

2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Radical Intermediates ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Boronic Esters ◽  
Carbon Centered Radical ◽  
Iron Based ◽  
High Yields

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.

scholarly journals DFT Study of Unstrained Ketone C-C Bond Activation via Rhodium(I)-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions

2019 ◽  
Author(s):  
Dengmengfei Xiao ◽  
Lili Zhao ◽  
Diego Andrada
Keyword(s):  
Density Functional ◽  
Bond Activation ◽  
Chemical Reactivity ◽  
Cross Coupling ◽  
Underlying Mechanism ◽  
Reductive Elimination ◽  
Coupling Reactions ◽  
Co Catalysts ◽  
Cross Coupling Reactions ◽  
Strain Model

Unstrained cyclic ketones can participate in cooperative Suzuki-Miyaura cross-coupling type reaction using rhodium(I)-based catalyst via C-C bond activation. The regioselectivity indicates a trend where the most substituted side is activated and it is controlled by the beta-substituents. In this work, Density Functional Theory (DFT) calculations have been carried out to disclose the underlying mechanism in the reaction of a ketone series and arylboronate using ylidene as ancillary ligand and pyridine as co-catalysts. The computed energies suggest the reductive elimination step with the highest energy while the reductive elimination has the highest energy barrier. By the means of the Activation Strain Model (ASM) of chemical reactivity, it is found that the ketone strain energy released on the oxidative addition does not control the relativity of the OA reactivity, but indeed is the interaction energy between Rh(I) and C-C bond the ruling effect. The effect of the beta-substituents on regioselectivity has been additionally studied.

ChemInform Abstract: Pd-Catalyzed sp2-sp Cross-Coupling Reactions Involving C-F Bond Activation in Highly Fluorinated Nitrobenzene Systems.

ChemInform ◽  
2013 ◽  
Vol 44 (23) ◽  
pp. no-no
Author(s):  
Matthew R. Cargill ◽  
Graham Sandford ◽  
Pinar Kilickiran ◽  
Gabriele Nelles
Keyword(s):  
Bond Activation ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions

scholarly journals Argentate(i) and (iii) complexes as intermediates in silver-mediated cross-coupling reactions

2018 ◽  
Vol 54 (40) ◽  
pp. 5086-5089 ◽  
Author(s):  
Sebastian Weske ◽  
Richard A. Hardin ◽  
Thomas Auth ◽  
Richard A. J. O’Hair ◽  
Konrad Koszinowski ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Esi Mass Spectrometry

Silver-mediated cross-coupling reactions proceed via anionic ate complexes, which have been characterized by a combination of NMR spectroscopy, ESI mass spectrometry, and quantum-chemical calculations.

Deoxygenative Transition-Metal-Promoted Reductive Coupling and Cross-Coupling of Alcohols and Epoxides

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 267-278
Author(s):  
Kenneth M. Nicholas ◽  
Chandrasekhar Bandari
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Transition Metal Catalysts ◽  
Coupling Reactions ◽  
Reductive Coupling ◽  
Practical Applications ◽  
Cross Coupling Reactions ◽  
Carbon Carbon Bond

AbstractThe prospective utilization of abundant, CO2-neutral, renewable feedstocks is driving the discovery and development of new reactions that refunctionalize oxygen-rich substrates such as alcohols and polyols through C–O bond activation. In this review, we highlight the development of transition-metal-promoted reactions of renewable alcohols and epoxides that result in carbon–carbon bond-formation. These include reductive self-coupling reactions and cross-coupling reactions of alcohols with alkenes and arene derivatives. Early approaches to reductive couplings employed stoichiometric amounts of low-valent transition-metal reagents to form the corresponding hydrocarbon dimers. More recently, the use of redox-active transition-metal catalysts together with a reductant has enhanced the practical applications and scope of the reductive coupling of alcohols. Inclusion of other reaction partners with alcohols such as unsaturated hydrocarbons and main-group organometallics has further expanded the diversity of carbon skeletons accessible and the potential for applications in chemical synthesis. Catalytic reductive coupling and cross-coupling reactions of epoxides are also highlighted. Mechanistic insights into the means of C–O activation and C–C bond formation, where available, are also highlighted.1 Introduction2 Stoichiometric Reductive Coupling of Alcohols3 Catalytic Reductive Coupling of Alcohols3.1 Heterogeneous Catalysis3.2 Homogeneous Catalysis4 Reductive Cross-Coupling of Alcohols4.1 Reductive Alkylation4.2 Reductive Addition to Olefins5 Epoxide Reductive Coupling Reactions6 Conclusions and Future Directions

scholarly journals Well-Defined Pre-Catalysts in Amide and Ester Bond Activation

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 215 ◽  
Author(s):  
Sandeep R. Vemula ◽  
Michael R. Chhoun ◽  
Gregory R. Cook
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Ester Bond ◽  
Coupling Reactions ◽  
Catalytic Systems ◽  
Design And Synthesis ◽  
Cross Coupling Reactions ◽  
Made In

Over the past few decades, transition metal catalysis has witnessed a rapid and extensive development. The discovery and development of cross-coupling reactions is considered to be one of the most important advancements in the field of organic synthesis. The design and synthesis of well-defined and bench-stable transition metal pre-catalysts provide a significant improvement over the current catalytic systems in cross-coupling reactions, avoiding excess use of expensive ligands and harsh conditions for the synthesis of pharmaceuticals, agrochemicals and materials. Among various well-defined pre-catalysts, the use of Pd(II)-NHC, particularly, provided new avenues to expand the scope of cross-coupling reactions incorporating unreactive electrophiles, such as amides and esters. The strong σ-donation and tunable steric bulk of NHC ligands in Pd-NHC complexes facilitate oxidative addition and reductive elimination steps enabling the cross-coupling of broad range of amides and esters using facile conditions contrary to the arduous conditions employed under traditional catalytic conditions. Owing to the favorable catalytic activity of Pd-NHC catalysts, a tremendous progress was made in their utilization for cross-coupling reactions via selective acyl C–X (X=N, O) bond cleavage. This review highlights the recent advances made in the utilization of well-defined pre-catalysts for C–C and C–N bond forming reactions via selective amide and ester bond cleavage.

Protocol for Palladium/N-Heterocyclic Carbene-Catalyzed Suzuki–Miyaura Cross-Coupling of Amides by N–C(O) Activation

Synthesis ◽  
2020 ◽  
Author(s):  
Peng Lei ◽  
Guangchen Li ◽  
Michal Szostak ◽  
Yun Ling ◽  
Jie An ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Room Temperature ◽  
Bond Activation ◽  
Process Development ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Amide Bonds ◽  
Cross Coupling Reactions ◽  
Synthetic Procedure ◽  
Operational Simplicity

AbstractAmides are among the most important and ubiquitous functional groups in organic chemistry and process development. In this Practical Synthetic Procedure, a protocol for the Suzuki–Miyaura cross-coupling of amides by selective N–C(O) bond activation catalyzed by commercially available, air- and moisture-stable palladium/N-heterocyclic carbene (NHC) complexes is described. The procedure described involves [Pd(IPr)(cin)Cl] [IPr = 2,6-(diisopropylphenyl)imidazol-2-ylidene, cin = cinnamyl] at 0.10 mol% at room temperature and is performed on decagram scale. Furthermore, a procedure for the synthesis of amide starting materials is accomplished via selective N-tert-butoxycarbonylation, which is the preferred method over N-acylation. The present protocol carries advantages of operational simplicity, commercial availability of catalysts, and excellent conversions at low catalyst loadings. The method is generally useful for activation of N–C(O) amide bonds in a broad spectrum of amide precursors. The protocol should facilitate the implementation of amide cross-coupling reactions.

Synthesis of Benzamide Derivatives by the Reaction of Arenes and Isocyanides through a C–H Bond Activation Strategy

Synlett ◽  
2017 ◽  
Vol 29 (01) ◽  
pp. 94-98 ◽  
Author(s):  
Mehdi Khalaj ◽  
Mahboubeh Taherkhani ◽  
Seyed Mousavi-Safavi ◽  
Jafar Akbari
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Benzene Derivatives ◽  
Formation Reaction ◽  
Cross Coupling Reactions ◽  
Carbon Carbon Bond ◽  
Benzamide Derivatives

A carbon–carbon bond formation reaction between isocyanides and benzene derivatives is reported. In contrast to traditional cross-coupling reactions, which require aryl halides or pseudohalides, we use a palladium catalyst to generate the aryl–palladium through C–H bond activation of arenes. This method offers an attractive approach to a range of benzamides from readily accessible benzene derivatives.

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