scholarly journals Ferrocenylimine Palladium (II) Complexes: Synthesis, Characterization and Application in Mizoroki-Heck and Suzuki-Miyaura Cross-Coupling Reactions

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 755
Author(s):  
Asanda C. Matsheku ◽  
Richard Tia ◽  
Munaka C. Maumela ◽  
Banothile C. E. Makhubela
Keyword(s):  
Density Functional ◽  
Aryl Halide ◽  
Cross Coupling ◽  
Analytical Techniques ◽  
13C Nmr Spectroscopy ◽  
Catalyst Loading ◽  
Moderate Activity ◽  
Coupling Reactions ◽  
Heck Reactions ◽  
Cross Coupling Reactions

Carbon-carbon cross-coupling reactions are essential synthetic tools for synthesizing polymers, natural products, agrochemicals, and pharmaceuticals. Therefore, new catalysts that function with greater efficiency and functional group tolerance are being researched. We have prepared new ferrocenylimine monodentate N and P donor ligands and N^N and N^P bidentate chelating ligands (L1 to L4) employed in stabilizing palladium ions for application in Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions. The ferrocenylimine ligands were successfully synthesized by Schiff base condensation reactions of acetyl ferrocene with hydrazine monohydrate to afford ferrocenyl hydrazone (L1). Ligand L1 was further treated with aldehydes to give ferrocenyl(2-diphenylphosphino)imine (L3) and ferrocenyl(pyridyl)imine (L3), while phosphination of L1 with chlorodiphenylphosphine afforded L2. The ligands were used to prepare new palladium(II) complexes (C1 to C4) by complexation with [PdCl2(MeCN)2]. All the ligands and complexes were fully characterized using standard spectroscopic and analytical techniques, including 1H NMR and 13C NMR spectroscopy, FT-IR spectroscopy, mass spectrometry and elemental analysis. The complexes (C1 to C4) were tested for efficacies in catalyzing Mizoroki-Heck and Suzuki-Miyaura C-C cross-coupling reactions and proved to be suitable catalyst precursors. Ferrocenyl(2-diphenylphosphine)imino and ferrocenyl-methyl hydrazone palladium(II) complexes C2 and C3 showed the best activities at TONs of up to 201. The ferrocenyl palladium(II) (pre)catalysts demonstrated moderate activity in Mizoroki-Heck reactions involving substrates with substituents on the olefin and aryl halide (including 4-Cl, 4-CH3, -CO2Me and -CO2Et). Density Functional Theory was used to study the mechanism of the Mizoroki-Heck cross-coupling reactions and have led to confirmation of the widely accepted catalytic cycle. Catalyst precursors (C1 to C4) also displayed good activity and selectivity in Suzuki-Miyaura cross-coupling reactions, at 0.5 mol% catalyst loading, with good tolerance to functional groups present on the aryl halide and boronic acid substrates (such as 4-Cl, 4-CHO, 4-COOH, 3-NO2, 3,5-dimethoxy and 4-CH3).

Cross-coupling reactions catalyzed by an N-heterocyclic carbene–Pd(ii) complex under aerobic and CuI-free conditions

RSC Advances ◽  
2014 ◽  
Vol 4 (57) ◽  
pp. 30447-30452 ◽  
Author(s):  
Hongfei Lu ◽  
Lin Wang ◽  
Feifei Yang ◽  
Runze Wu ◽  
Wei Shen
Keyword(s):  
Cross Coupling ◽  
Catalytic Reactions ◽  
Catalyst Loading ◽  
Coupling Reactions ◽  
Heck Reactions ◽  
Cross Coupling Reactions ◽  
Low Catalyst Loading

The catalytic reactions proceed with good yields with a low catalyst loading (1 mol%) under aerobic and CuI-free conditions for Sonogashira and Heck reactions.

scholarly journals Nickel versus Palladium in Cross-Coupling Catalysis: On the Role of Substrate Coordination to Zerovalent Metal Complexes

Synthesis ◽  
2019 ◽  
Vol 52 (04) ◽  
pp. 565-573 ◽  
Author(s):  
Alasdair K. Cooper ◽  
Paul M. Burton ◽  
David J. Nelson
Keyword(s):  
Functional Groups ◽  
Density Functional ◽  
Aryl Halide ◽  
Cross Coupling ◽  
Density Functional Theory Calculations ◽  
Detailed Comparison ◽  
Coupling Reactions ◽  
Functional Theory ◽  
Cross Coupling Reactions

A detailed comparison of the effect of coordinating functional groups on the performance of Suzuki–Miyaura reactions catalysed by nickel and palladium is reported, using competition experiments, robustness screening, and density functional theory calculations. Nickel can interact with a variety of functional groups, which manifests as selectivity in competitive cross-coupling reactions. The presence of these functional groups on exogenous additives has effects on cross-coupling reactions that range from a slight improvement in yield to the complete cessation of the reaction. In contrast, palladium does not interact sufficiently strongly with these functional groups to induce selectivity in cross-coupling reactions; the selectivity of palladium-catalysed cross-coupling reactions is predominantly governed by aryl halide electronic properties.

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.

scholarly journals Computational Insights into Intramolecular Cross-Coupling of Quaternary Borate Salts

2021 ◽  
Author(s):  
Florian Matz ◽  
Arif Music ◽  
Dorian Didier ◽  
Thomas C. Jagau
Keyword(s):  
Organic Synthesis ◽  
Energy Barrier ◽  
Density Functional ◽  
Bond Formation ◽  
Cross Coupling ◽  
Coupled Cluster ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Product Distributions ◽  
Borate Salts

Cross-coupling reactions for C-C bond formation represent a cornerstone of organic synthesis. In most cases, they make use of transition metals, which has several downsides. Recently, metal-free alternatives relying on electrochemistry have gained interest. One example of such a reaction is the oxidation of tetraorganoborate salts that initiates aryl-aryl and aryl-alkenyl couplings with promising selectivities. This work investigates the mechanism of this reaction computationally using density functional and coupled-cluster theory. Our calculations reveal a distinct difference between aryl-alkenyl and aryl-aryl couplings: While C-C bond formation occurs irreversibly and without an energy barrier if an alkenyl residue is involved, many intermediates can be identified in aryl-aryl couplings. In the latter case, intramolecular transitions between reaction paths leading to different products are possible. Based on the energy differences between these intermediates, we develop a kinetic model to estimate product distributions for aryl-aryl couplings.<br>

scholarly journals Computational Insights into Intramolecular Cross-Coupling of Quaternary Borate Salts

2021 ◽  
Author(s):  
Florian Matz ◽  
Arif Music ◽  
Dorian Didier ◽  
Thomas C. Jagau
Keyword(s):  
Organic Synthesis ◽  
Energy Barrier ◽  
Density Functional ◽  
Bond Formation ◽  
Cross Coupling ◽  
Coupled Cluster ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Product Distributions ◽  
Borate Salts

Cross-coupling reactions for C-C bond formation represent a cornerstone of organic synthesis. In most cases, they make use of transition metals, which has several downsides. Recently, metal-free alternatives relying on electrochemistry have gained interest. One example of such a reaction is the oxidation of tetraorganoborate salts that initiates aryl-aryl and aryl-alkenyl couplings with promising selectivities. This work investigates the mechanism of this reaction computationally using density functional and coupled-cluster theory. Our calculations reveal a distinct difference between aryl-alkenyl and aryl-aryl couplings: While C-C bond formation occurs irreversibly and without an energy barrier if an alkenyl residue is involved, many intermediates can be identified in aryl-aryl couplings. In the latter case, intramolecular transitions between reaction paths leading to different products are possible. Based on the energy differences between these intermediates, we develop a kinetic model to estimate product distributions for aryl-aryl couplings.<br>

scholarly journals Ni-Catalyzed Electrochemical C(sp2)−C(sp3) Cross-Coupling Reactions

2020 ◽  
Author(s):  
Jian Luo ◽  
Bo Hu ◽  
wenda wu ◽  
maowei hu ◽  
Tianbiao Liu
Keyword(s):  
Aryl Halide ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Ambient Conditions ◽  
Acid Modification ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Organozinc Reagents ◽  
Industrial Adoption

Nickel (Ni) catalyzed carbon-carbon (C−C) cross-coupling has been considerably developed in last decades and has demonstrated unique reactivities compared to palladium. However, existing Ni catalyzed cross-coupling reactions, despite success in organic synthesis, are still subject to the use of air-sensitive nucleophiles (i.e. Grignard and organozinc reagents), or catalysts (i.e. Ni<sup>0</sup> pre-catalysts), significantly limiting their academic and industrial adoption. Herein, we report that, through electrochemical voltammetry screening and optimization, the redox neutral C(sp<sup>2</sup>)‒C(sp<sup>3</sup>) cross-coupling can be accomplished in an undivided cell configuration using bench-stable aryl halide or β-bromostyrene (electrophiles) and benzylic trifluoroborate (nucleophiles) reactants, non-precious, bench stable catalysts consisting of NiCl<sub>2</sub>•glyme pre-catalyst and polypyridine ligands under ambient conditions. The broad reaction scope and good yields of the Ni-catalyzed electrochemical coupling reaction were confirmed by 48 examples of aryl/β-styrenyl chloride/bromide and benzylic trifluoroborates. Its potential applications were demonstrated by late-stage functionalization of pharmaceuticals and natural amino acid modification. Furthermore, this electrochemical C−C cross-coupling reaction was demonstrated at gram-scale in a flow-cell electrolyzer for practical industrial adoption. Finally, an array of chemical and electrochemical studies mechanistically indicates that electrochemical C−C cross-coupling reaction proceeds through an unconventional radical trans-metalation mechanism.

scholarly journals Ni-Catalyzed Electrochemical C(sp2)−C(sp3) Cross-Coupling Reactions

2020 ◽  
Author(s):  
Jian Luo ◽  
Bo Hu ◽  
wenda wu ◽  
maowei hu ◽  
Tianbiao Liu
Keyword(s):  
Aryl Halide ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Ambient Conditions ◽  
Acid Modification ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Organozinc Reagents ◽  
Industrial Adoption

Nickel (Ni) catalyzed carbon-carbon (C−C) cross-coupling has been considerably developed in last decades and has demonstrated unique reactivities compared to palladium. However, existing Ni catalyzed cross-coupling reactions, despite success in organic synthesis, are still subject to the use of air-sensitive nucleophiles (i.e. Grignard and organozinc reagents), or catalysts (i.e. Ni<sup>0</sup> pre-catalysts), significantly limiting their academic and industrial adoption. Herein, we report that, through electrochemical voltammetry screening and optimization, the redox neutral C(sp<sup>2</sup>)‒C(sp<sup>3</sup>) cross-coupling can be accomplished in an undivided cell configuration using bench-stable aryl halide or β-bromostyrene (electrophiles) and benzylic trifluoroborate (nucleophiles) reactants, non-precious, bench stable catalysts consisting of NiCl<sub>2</sub>•glyme pre-catalyst and polypyridine ligands under ambient conditions. The broad reaction scope and good yields of the Ni-catalyzed electrochemical coupling reaction were confirmed by 48 examples of aryl/β-styrenyl chloride/bromide and benzylic trifluoroborates. Its potential applications were demonstrated by late-stage functionalization of pharmaceuticals and natural amino acid modification. Furthermore, this electrochemical C−C cross-coupling reaction was demonstrated at gram-scale in a flow-cell electrolyzer for practical industrial adoption. Finally, an array of chemical and electrochemical studies mechanistically indicates that electrochemical C−C cross-coupling reaction proceeds through an unconventional radical trans-metalation mechanism.

scholarly journals Dimethylisosorbide (DMI) as a Bio-Derived Solvent for Pd-Catalyzed Cross-Coupling Reactions

Synlett ◽  
2018 ◽  
Vol 29 (17) ◽  
pp. 2293-2297 ◽  
Author(s):  
Allan Watson ◽  
Kirsty Wilson ◽  
Jane Murray ◽  
Helen Sneddon ◽  
Craig Jamieson
Keyword(s):  
Chemical Industry ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Heck Reactions ◽  
Bond Forming ◽  
Cross Coupling Reactions ◽  
Bond Forming Reactions ◽  
Palladium Catalyzed ◽  
Catalyzed Reactions

Palladium-catalyzed bond-forming reactions, such as the ­Suzuki–Miyaura and Mizoroki–Heck reactions, are some of the most broadly utilized reactions within the chemical industry. These reactions frequently employ hazardous solvents; however, to adhere to increasing sustainability pressures and restrictions regarding the use of such solvents, alternatives are highly sought after. Here we demonstrate the utility of dimethyl isosorbide (DMI) as a bio-derived solvent in several benchmark Pd-catalyzed reactions: Suzuki–Miyaura (13 examples, 62–100% yield), Mizoroki–Heck (13 examples, 47–91% yield), and Sonogashira (12 examples, 65–98% yield).

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