Cross-coupling Reactions Research Articles

Regio-MPNN: predicting regioselectivity for general metal-catalyzed cross-coupling reactions using a chemical knowledge informed message passing neural network

As a fundamental problem in organic chemistry, regioselectivity is crucial in designing energy and cost-efficient reaction pathways for target compounds.

Unexpectedly superior efficiency of chloride-directed double Suzuki–Miyaura cross-coupling reactions to bromide-directed reactions for the synthesis of sterically hindered 2,7-diaryl fluorenes

Sterically hindered 2,7-diaryl fluorenes have been efficiently synthesized via double Suzuki–Miyaura cross-coupling reactions of challenging 2,7-dichlorofluorene with multiple di-ortho-substituted arylboronic acids using the NHC–Pd catalyst INPd.

PREPARATION, CHARACTERIZATION, AND STUDY OF THE BIOLOGICAL ACTIVITY OF 5-CHLORO-8-QUINOLINOL DERIVATIVES AND ITS COORDINATION WITH THE NICKEL (II) AND DIPHOSPHINES

Nickel complexes are effective catalysts for cross-coupling reactions between alkyl Grignard reagents and alkenyl–S and alkenyl–Se compounds. In this study, various organic compounds were prepared. Ethylnyl 2-((5-chloro-8-quinolinol)oxy) acetate compound (designated as A1) was synthesized by adding potassium carbonate to quinoline and ethyl chloroacetate. The second compound 2-((5-chloro-8- quinolinol)oxy) acetohydrazide (A2) were obtained by reacting A1with hydrazide. Complex compound A3 were obtained by reacting equimolar amounts of compound A2 with the nickel salt solution, using ethanol as the solvent. Phosphinate complexes were prepared by reacting equal moles of the A3 with the various phosphines and using ethanol as a solvent. The synthesized compounds and complexes were characterized using various spectroscopic techniques, including (FT-IR) spectroscopy, (31P-{ 1H}- 13C-NMR) spectroscopy, and C.H.N. analysis. Additionally, their melting points, purity, molar conductivity, and magnetic susceptibility were determined. The impact of some prepared compounds and complexes on the growth of two antibiotic-resistant bacterial strains, namely the Gram-negative Staphylococcus and the Gram-positive Escherichia coli, was studied. Amoxicillin was used as control antibiotics. Some of the synthesized compounds exhibited significant inhibitory activity against the tested bacterial strains. The A2 compound readily forms complexes, especially with nickel, manganese, and copper salts. The prepared compounds and complexes exhibited high stability and strength, maintaining their structure, color, and melting point even under varying laboratory temperatures between winter and summer

Expression of concern: Palladium nanoparticles supported on 1,3-dicyclohexylguanidine functionalized mesoporous silica SBA-15 as highly active and reusable catalyst for the Suzuki–Miyaura cross-coupling reaction

Expression of concern for ‘Palladium nanoparticles supported on 1,3-dicyclohexylguanidine functionalized mesoporous silica SBA-15 as highly active and reusable catalyst for the Suzuki–Miyaura cross-coupling reaction’ by Hojat Veisi et al., RSC Adv., 2015, 5, 20098–20107, https://doi.org/10.1039/C4RA14668A.

The coordination of alkali-metal nickelates to organic π-systems: synthetic, structural and spectroscopic insights.

Low-valent nickelates have recently been shown to be key intermediates in challenging cross-coupling reactions using aryl ethers as electrophiles. Key for the success of these transformations is the activation of the substrate through π-coordination to the nickelate intermediate, however there is still limited knowledge about the fundamental structure and coordination chemistry of these heterobimetallic complexes. Herein, we report the synthesis, structures, and spectroscopic analysis of a diverse family of alkali-metal nickelates derived from phenyl-alkali-metal reagents and Ni(ttt-CDT), where ttt-CDT = trans,trans,trans-1,5,9-cyclododecatriene. The co-complexation of PhLi with Ni(ttt-CDT) was found to yield 1 : 1, 2 : 1 or 4 : 2 lithium nickelates depending on the stoichiometry and reaction conditions employed. The high lability of the ttt-CDT ligand enables facile ligand exchange with an assorted series of organic π-acceptors, ranging from polyaromatic hydrocarbons to ketones, imines and nitriles. For anthracene and phenanthrene, a homologous series of Li, Na and K nickelates could be obtained, which lead to different structural motifs or degrees of aggregation in the solid-state spanning solvated monomers to complex polymeric arrangements. For π-extended systems such as perylene or coronene, competing single-electron-transfer to give the corresponding radical anions was observed, illustrating the highly reducing nature of the alkali-metal nickelates. X-ray crystallographic analysis and NMR spectroscopy of the phenyl-alkali-metal nickelates reveal extreme back-bonding from Ni(0) to the organic π-acceptors due to strong σ-donation from the carbanionic ligands.

Visible light-induced halogen-atom transfer by N-heterocyclic carbene-ligated boryl radicals for diastereoselective C(sp3)-C(sp2) bond formation.

Photoinduced halogen-atom transfer (XAT) has rapidly emerged as a programmable approach to generate carbon-centered radical intermediates, mainly relying on silyl and α-aminoalkyl radicals as halogen abstractors. More recently, ligated boryl radicals have also been proposed as effective halogen abstractors under visible-light irradiation. In this study, we describe the use of this approach to enable C(sp3)-C(sp2) bond formation via radical addition of carbon-centered radicals generated via XAT onto chloroalkynes. Our mechanistic investigation reveals a complex interplay of highly reactive radical intermediates which, under optimized conditions, delivered the targeted vinyl chlorides in excellent yields and Z : E ratios. Finally, we demonstrated the synthetic value of these products in transition metal-based cross-coupling reactions.

Establishing the main determinants of the environmental safety of catalytic fine chemical synthesis with catalytic cross-coupling reactions

Bio-risk assessment was conducted for Sonogashira and Mizoroki–Heck reactions. bio-Strips showed the cytotoxicity of the reaction components. The study suggests the rules of eco-friendly design for future catalytic processes.

Palladium-catalyzed Suzuki-Miyaura cross-coupling of carboxylic-phosphoric anhydrides via C-O bond cleavage.

A robust palladium-catalyzed Suzuki-Miyaura reaction of carboxylic-phosphoric anhydrides via highly selective C(O)-O bond cleavage under inorganic base-free conditions has been reported. Carboxylic-phosphoric anhydrides, generated through activating carboxylic acids using phosphates by esterification or direct dehydrogenative reaction with phosphites, have been employed as highly reactive electrophiles for Suzuki-Miyaura cross-coupling reactions. Broad substrate scope and excellent functional group tolerance have been demonstrated to be a general and practical approach for the synthesis of highly valuable ketones.

Retraction: Synthesis and characterization of a supported Pd complex on volcanic pumice laminates textured by cellulose for facilitating Suzuki-Miyaura cross-coupling reactions.

[This retracts the article DOI: 10.1039/D0RA04521G.].

Bio-based palladium catalyst in cryogel for cross-coupling reactions

A phenylalanine-based palladium catalyst was developed for the Suzuki–Miyaura reaction, preventing palladium leaching. It demonstrated high yield (up to 99%) in aqueous media and can be reused up to seven times, making it scalable for industrial use.

Electrochemical nickel-catalyzed cross-coupling of glycosyl thiols with preactivated phenols and ketones.

An efficient electrochemical nickel-catalyzed cross-coupling reaction has been reported here for the synthesis of S-glycosides from preactivated phenols and ketones under mild conditions. Various glycosyl thiols, including unprotected sugar, and a diverse range of aryl/alkenyl triflates, including some complex biorelevant phenols and ketones, were well tolerated in this method.

Synthesis of allenynes via Pd-catalyzed coupling of 1,4-diyn-3-yl carbonates with boronic acids

A palladium-catalyzed cross-coupling reaction of 1,4-diyn-3-yl carbonates with organoboronic acids for a series of conjugated allenynes using S-phos or Gorlos-phos as the ligand under mild conditions has been developed.

Nickel-catalyzed C(sp2)-C(sp3) coupling via photoactive electron donor-acceptor complexes.

We have developed a novel Ni-catalyzed reductive cross-coupling reaction of aryl bromides and alkyl iodides via a photoactive electron donor-acceptor (EDA) complex. This photo-induced process enables the efficient construction of C(sp2)-C(sp3) bonds in the absence of an external photocatalyst. Electronically and structurally diverse aryl bromides, as well as secondary and primary alkyl iodides could undergo this transformation smoothly. Natural product derivatives were employed successfully, and UV-vis spectroscopy was utilized to gain mechanistic insight.

Desulfitative Sonogashira cross-coupling of thiopyronin for the synthesis of NIR arylacetylene-containing rhodamines.

A classical, safe and efficient red-shift strategy contributing to NIR arylacetylene-containing rhodamines has been developed via the desulfitative Sonogashira cross-coupling reaction of thiopyronin for the first time, exhibiting a broad substrate scope with good yields. In addition, compound 3m shows great potential for application as a singlet oxygen probe, demonstrating the practicality of the method.

Palladium-catalyzed syn-alkynylarylation of internal alkynes: rapid access to all-carbon tetrasubstituted alkenes.

Herein, a straightforward method for rapid access to all-carbon tertrasubstituted alkenes bearing alkyl, aryl and alkynyl groups is established via palladium-catalyzed three-component cross-coupling reaction of internal alkynes, haloalkynes and arylboronic acids. This protocol is characterized by a broad substrate scope and excellent chemo- and regioselectivities. The dual beneficial roles of silver salts in activating haloalkynes and inhibiting bromoalkynylation have been demonstrated by serving as both the Lewis acid and halide scavenger.

Iridium/palladium dual photocatalysis for oxidative decarboxylative esterification of alcohols using α-keto acids

Herein, we report an unprecedented oxidative decarboxylative C–O cross-coupling reaction for the esterification of feedstock α-keto carboxylic acids and alcohols under mild conditions.

A suitably fabricated ternary nanocomposite (Cu-CuO@rGO-SiO2) as a sustainable and common heterogeneous catalyst for C-S, C-O and C-N coupling reactions.

A hybrid composite based on π-electron rich reduced graphene oxide (rGO) and mesoporous silica (SiO2) was prepared and decorated with copper species to afford a ternary nanocomposite material (Cu-CuO@rGO-SiO2). This copper-based nanocomposite was successfully used as a robust and multi-tasking heterogeneous catalyst for most common cross-coupling reactions (e.g. C-S, C-O and C-N coupling). A broad range of catalytic activities are believed to be originated from the synergism of different co-existing copper species (Cu(0) and CuO) and facile charge transfer from the metal ions towards rGO-SiO2 matrices, as established from XPS and other studies.

Copper-catalyzed crosscoupling of vinyl nitrenes and CF3-carbenes to synthesize CF3-2-azadienes

A unique and efficient copper catalytic system has been established for the synthesis of fluorinated 2-azadienes from isoxazoles and CF3-N-tosylhydrazones via crosscoupling reactions of vinyl nitrenes with fluoroalkyl carbenes.

Molecular engineering of 3-arylated tetrazo[1,2-b]indazoles: divergent synthesis and structure-property relationships.

The synthetic scope of 3-arylated tetrazo[1,2-b]indazoles is reported based on a Pd-catalyzed Liebeskind-Srogl cross-coupling reaction followed by an N-cyclisation process. The reactivity of the nitrogen atoms was used to further diversify these N-rich polyaromatic tetrazo[1,2-b]indazoles in a panel of reactions (protonation, selective oxidation, metallations). Selective ortho-C-H activation/functionalization on the heterocycle was also demonstrated with three transition metals (TM = Pd, Ir and Rh). The effects of all these molecular engineering strategies, particularly the N-modifications, on the optical and redox properties of the 3-arylated tetrazoindazoles were studied experimentally and theoretically. This study highlights the diversity of molecular structures and electronic properties offered by the tetrazo[1,2-b]indazole platform.

Copper-Based Solid Wastes Promoted Cross-Coupling Reactions of Terminal Alkynes

Copper-Based Solid Wastes Promoted Cross-Coupling Reactions of Terminal Alkynes