Coupling Reaction Of Aryl Iodides Research Articles

Construction of Fe3O4@Dop-Triazine-CuCl2 as a novel and green nanocatalyst for C–Se coupling reaction of heterocyclic compounds

In this research, we first fabricated Fe3O4@Dop-Triazine-CuCl2 nanocatalyst by simple method, then its catalytic activity was investigated in the preparation of various derivatives of aryl-heteroaryl and di-heteroaryl selenides through C–Se coupling reactions of aryl iodides with powder selenium and various derivatives of heterocyclic compounds (with active C–H bonds). The catalyst exhibited spherical morphology with a diameter of approximately 20–30 nm and a magnetic saturation moment of 50.032 emu/g. The hydrocarbon content was measured to be around 12% by weight. In this method, a wide range of aryl-heteroaryl and di-heteroaryl selenides (36 examples) were synthesized with high yields (85–97%) using catalytic amount of the Fe3O4@Dop-Triazine-CuCl2 nanomaterial in the presence of KHCO3 in [BMIM]PF6 as solvent. This method has several remarkable features, which can be mentioned as follows: the synthesis of aryl-heteroaryl and di-heteroaryl selenide derivatives with high yields, performing the reactions in a suitable time (4 h), the applicability of this catalytic system for a wide range of substrates, the use of ionic liquid as solvent, high efficiency of Fe3O4@Dop-Triazine-CuCl2 catalyst, simple separation and high reusability of nanocatalyst.

Low‐valent Tungsten Catalyzed Carbonylative Sonogashira Coupling Reactions of Aryl Iodides with Alkynes

AbstractA low‐valent tungsten catalyzed carbonylative Sonogashira coupling reactions has been established. The present protocol utilizes inexpensive and readily available W(CO)6 as precatalyst and proceeds in the presence of atmospheric CO, providing a practical method to a series of functionalized alkynones and indoxyls compounds under mild reaction conditions. Moreover, the simple reaction system, good functional group tolerance and broad substrate scope enable the application of this transformation in the synthesis of functionalized carbonyl‐containing molecules.

Application of 1,4-pentanediol as a renewable solvent for copper-catalyzed Ullmann-type coupling reactions

It was demonstrated that 1,4-pentanediol as a biomass-originated polar protic solvent could be utilized as an alternative reaction medium for copper-catalyzed Ullmann-type coupling reactions of aryl iodides and various amines under mild conditions. The effect of the copper source, the base, the water, and the γ-valerolactone content of the reaction mixture on the reaction performance was investigated. Eighteen cross-coupling products were isolated with yields of 11–69 %, and high purity (>98 %). Two O-arylated products, 4-phenoxypentan-1-ol and 5-phenoxypentan-2-ol were characterized. The recycling of the solvents after product isolation was also demonstrated. These results represent an example that proves that biomass-derived safer solvents can be utilized in common, industrially important transformations.

Bimetallic AuNi nanoparticles supported on mesoporous MgO as catalyst for Sonogashira-Hagihara cross-coupling reaction

Gold catalysts have been reported to be applied only for the Sonogashira-Hagihara reaction of iodobenzene and phenylacetylene under harsh reaction conditions, while the scope of the reaction has not been expanded for coupling reaction of other aryl halides and alkynes. In this investigation, a cost-effective, Pd-free catalyst based on mesoporous magnesium oxide supported bimetallic AuNi nanoparticles (m-MgO@AuNi) have been synthesized by hydrothermal method and its efficiency has been demonstrated in Sonogashira-Hagihara cross-coupling reaction. The m-MgO@AuNi nanocatalyst was structurally and morphologically characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and the mesoporous structure of MgO has been confirmed through BET analysis. Using this palladium-free catalyst, Sonogashira-Hagihara coupling reaction of aryl iodides and aryl bromides with alkynes have been successfully performed and catalyst was recycled for several times. The results demonstrate that the synergistic effect between Au, Ni and mesoporous MgO support plays key role in enhancement of m-MgO@AuNi catalytic activity in Sonogashira-Hagihara reaction.

Enantioselective construction of axially chiral cyclohexylidene scaffolds via Pd-catalyzed asymmetric coupling reaction

Axially chiral cyclohexylidenes exhibit unique chirality because of the restricted rotation of the C=C bond. Compared with other axially chiral compounds, they are much less explored, and their efficient construction remains a synthetic challenge. Herein, we report the first palladium-catalyzed asymmetric coupling reaction of aryl iodides with 4-substituted cyclohexanol-derived α-diazocarbonyl compounds to give tetrasubstituted cyclohexylidenes in good yields (up to 92%) with excellent enantioselectivities (up to 96% ee ) under mild conditions. This protocol provides a general access to axially chiral cyclohexylidenes. The utility of this unique scaffold was demonstrated by the carboxylic acid serving as a useful chiral ligand in transition-metal-catalyzed C–H bond activation, which showed great promise as a new type of olefin ligand. • Pd-catalyzed asymmetric cross-coupling reaction • Facile access to enantioenriched axially chiral tetrasubstituted alkenes • Broad scope, good yields, and excellent enantioselectivities • Develop skeleton applications Tetrasubstituted alkenes are important building blocks in many natural products, drugs, and functional materials. Their efficient regio- and stereoselective synthesis poses a significant challenge to synthetic organic chemists due to the crowded nature of the double bonds. The reported palladium/Xu-Phos-catalyzed asymmetric coupling reaction of this method allows the use of readily available simple aryl iodides and 4-substituted cyclohexanol-derived α-diazocarbonyl compounds under mild conditions, furnishing a variety of tetrasubstituted cyclohexylidenes in good yields with excellent enantioselectivities. The utility of this unique scaffold was demonstrated by the carboxylic acid serving as a useful chiral ligand in transition-metal-catalyzed C–H bond activation, which showed great promise as a new type of olefin ligand. The first Pd/Xu-Phos-catalyzed asymmetric coupling reaction of aryl iodides with β -hydroxy α -diazocarbonyl compounds has been established to construct axially chiral cyclohexylidene skeletons (up to 92% yield, up to 96% ee ). This protocol provides easy access to axially chiral cyclohexylidenes, one rarely explored class of the atropisomeric family. The carboxylic acid derivatives could serve as a useful chiral ligand in transition-metal-catalyzed C–H bond activation. The proposed mechanism involves palladium carbene asymmetric migration insertion, β -hydroxyl elimination, and reduction of Pd(II) to Pd(0).

Cover Feature: Two β‐Diketiminate Zinc Complexes with 1‐D Chain and Dinuclear Topologies: Synthesis, Structures, and Catalytic Behavior (Eur. J. Inorg. Chem. 20/2022)

The Cover Feature shows the similarity of [L1Zn2Et2]n with the long ribbon of Nezha's hand. Nezha is a Chinese myth hero. One of his magic weapons is the “huntianling”, which is an infinite and soft ribbon. This ribbon is very powerful; it could cause chaos for the sun, moon and stars, and chop oceans and cut waves. [L1Zn2Et2]n displays a one-dimensional chain structure. To the best of our knowledge, it is the first β-diketiminate zinc complex that exhibits an infinite chain topology. It was employed to catalyze the coupling reaction of aryl iodides with B2Pin2 under milder conditions, with high functional group tolerance and a wide range of substrate scopes. Thus, it resembles the “huntianling” of Nezha both in structure and functionality. More information can be found in the Research Article by Y. Li and co-workers.

Two β‐Diketiminate Zinc Complexes with 1‐D Chain and Dinuclear Topologies: Synthesis, Structures, and Catalytic Behavior

AbstractTwo zinc complexes, [L1Zn2Et2]n (1) and [L2Zn2Et2] (2), were synthesized by reacting bis(β‐diketiminate) ligands H2L1 and H2L2 with ZnEt2. X‐ray single‐crystal diffraction analysis indicated that compound 1 displays a novel one‐dimensional chain structure. Compound 2 is dinuclear. The two compounds were employed to catalyze the coupling reaction of aryl iodides with B2Pin2. They were both catalytically active toward this transformation. Compound 1 exhibited higher catalytic activity than that of complex 2. The borylation reactions catalyzed by 1 possess the features of milder conditions, high functional group tolerance and wide range of substrate scopes.

Zeolitic imidazolate frameworks-67 (ZIF-67) supported PdCu nanoparticles for enhanced catalytic activity in Sonogashira-Hagihara and nitro group reduction under mild conditions

A bimetallic PdCu supported on amine functionalized ZIF-67 is shown to be efficient catalyst in Sonogashira-Hagihara coupling reaction of aryl iodides at room temperature and aryl bromides at 40 ºC. In addition, the catalyst is used in the reduction of 4-nitrophenol (4-NP) at room temperature. The analyses of several experiments are developed in order to demonstrate the existence of synergetic affects between Pd, Cu and Co particles in the named reactions. The stability and reusability of this catalyst are also assessed and its efficiency is compared with other reported catalysts in the same transformations.

Robust alkyl‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes anchored on Merrifield's resin as active catalysts for the selective synthesis of flavones and alkynones

Highly active and efficient propylene‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes covalently anchored on Merrifield's resin were synthesized and characterized using various physical and spectroscopic techniques. The two anchored Pd(II) complexes consist of the system: Merrifield's resin‐linker‐bis(NHC)Pd(II), the linkers being benzyl and benzyl‐O‐(CH2)3 for (Pd‐NHC1@M) and (Pd‐NHC2@M), respectively. The short linker anchored bis‐benzimidazolium ligand precursor (PBBI‐1@M) was synthesized via direct carbon–nitrogen alkylation of a propylene‐bridged bis(benzimidazole) (PBBI‐1) by Merrifield's resin chlorobenzyl group. The longer linker anchored bis‐benzimidazolium ligand precursor (PBBI‐2@M) was obtained in a two‐step reaction involving first alkylation of (PBBI‐1) with 3‐chloro‐1‐propanol followed by a nucleophilic substitution at Merrifield's resin chlorobenzyl group. Both supported ligand precursors (PBBI‐1@M and PBBI‐2@M) reacted with palladium acetate to produce the two heterogeneous catalysts (Pd‐NHC1@M) and (Pd‐NHC2@M). 13C NMR palladation shift of the benzimidazole N–C–N (C2) carbon was found very similar in both the liquid NMR spectra of the homogeneous complexes and the CP/MASS spectra of the corresponding covalently anchored complexes. The catalytic activity, stability, and the recycling ability of the supported catalysts have been investigated in the carbonylative Sonogashira coupling reactions of aryl iodides with aryl alkynes and alkyl alkynes and also in the cyclocarbonylative Sonogashira coupling reactions of aryl iodides with aryl alkynes via one pot reactions. The longer linker catalyst Pd‐NHC2@M demonstrated excellent catalytic activity, stability, and very high recycling ability in the two carbonylative coupling reactions. These systems exhibit the hypothesized thermodynamic stability offered by the chelate effect in addition to the strong sigma donor ability of a bis(NHC) ligand system generating electron‐rich palladium centers that favor the oxidative addition step of the aryl halide.

Carbonylative Suzuki–Miyaura Coupling Reactions of Aryl Iodides with Readily Available Polymer-Immobilized Palladium Nanoparticles

Polysilane/alumina-supported palladium nanoparticle catalyzed carbonylative Suzuki–Miyaura coupling reactions under ligand-free conditions have been developed to synthesize diaryl ketones. High yields and selectivities were achieved even with low catalyst loading under atmospheric pressure of CO gas. A variety of aryl iodides and arylboronic acids could be utilized to afford the diaryl ketones in excellent yields. Moreover, the ligand-free immobilized palladium nanoparticles could be recovered by simple filtration and the catalytic activity could be maintained for several runs.

Soft Heteroleptic N-Heterocyclic Carbene Palladium(II) Species for Efficient Catalytic Routes to Alkynones via Carbonylative Sonogashira Coupling.

N,N′-Substituted di-isopropyl (NHC-1), benzyl-isopropyl (NHC-2), and adamantyl-isopropyl (NHC-3) benzimidazolium salts react with palladium(II) bromide in pyridine to afford the corresponding trans-dibromidopyridinepalladium(II) complexes Pd-C1, Pd-C2, and Pd-C3 in high yields. A distorted square planar geometry for Pd-C2 and Pd-C3 was confirmed by single-crystal X-ray diffraction. The palladium(II) complexes show a remarkably higher catalytic activity and selectivity, compared to the literature data, in carbonylative Sonogashira coupling reactions of aryl iodides and aryl diiodides with aryl alkynes, alkyl alkynes, and dialkynes. Excellent yields with as low as 0.03 mol % loading of the catalyst were obtained. In the series of benzimidazolium (NHC) precursors, the 1H NMR signals of the α hydrogen show a consistent probing of the N-substituent donor strength. The density functional theory (DFT) quantum mechanical descriptors of the frontier orbitals were calculated. A linear correlation of the calculated absolute softness of the complexes versus the calculated percent buried volume (%Vbur) of their corresponding ligands was obtained. The catalytic activity experimental data are consistent with the hard soft acid base (HSAB)-predicted high affinity of the softest Pd-C3 complex for soft substrates, such as aryl iodides.

Copper-Catalyzed Methylthiolation of Aryl Iodides and Bromides with Dimethyl Disulfide in Water

An efficient route to aryl methyl sulfides through the copper-catalyzed coupling reaction of aryl iodides or bromides with dimethyl disulfide in water is described. Electron-donating and electron-withdrawing functional groups in the substrates were tolerated, and the corresponding products were obtained in moderate to good yields.

Chitosan supported Pd0 nanoparticles encaged in Al or Al-Fe pillared montmorillonite and their catalytic activities in Sonogashira coupling reactions

In this study, the excellent chelating capability of chitosan (CS) and remarkable physical properties of Al or Al-Fe pillared montmorillonite (Mt) (i.e. high adsorption/diffusion capacity, thermal stability, and mechanical property, etc.) have been combined into a composite material to support Pd0 nanoparticles catalysts. The BET surface area of the resultant Pd0@CS/Al-Mt and Pd0@CS/Al-Fe-Mt were observed as 63.2 m2·g−1 and 109.7 m2·g−1, respectively. CS chains and Pd0 nanoparticles (sized up to 3 nm) were well encaged in the interlayer spaces of the pillared Mt. The resultant catalysts showed high catalytic efficiency and excellent stability for Sonogashira coupling reactions of aryl iodides or bromides with terminal aryl alkynes. It was found that the comprehensive properties of Pd0@CS/Al-Fe-Mt catalyst was higher than that of Pd0@CS/Al-Mt catalyst, which was mainly attributed to the higher specific surface area and smaller-sized Pd0 nanoparticles.

Facile fabrication of magnetically separable palladium nanoparticles supported on modified kaolin as a highly active heterogeneous catalyst for Suzuki coupling reactions

In this study, Fe3O4 loaded Schiff base modified kaolin was prepared as a new support and palladium nanoparticles were anchored on it without any additional reducing agent (Pd NPs@Kao/Fe3O4/Pyr). Characterization studies demonstrated that Pd NPs@Kao/Fe3O4/Pyr was successfully designed and the size of particles was about 25 nm. Pd NPs@Kao/Fe3O4/Pyr was then utilized as catalyst in the preparation of biaryl compounds via Suzuki cross coupling reactions. Catalytic tests showed that Pd NPs@Kao/Fe3O4/Pyr acted as a highly active heterogeneous nanocatalyst in the coupling reaction of aryl iodides, bromides and chlorides containing different functional groups. Moreover, it was found that Pd NPs@Kao/Fe3O4/Pyr was successfully used in consecutive recycling tests and gave an 89% yield even after ten runs. In addition to the high catalytic behavior and reusability, Pd NPs@Kao/Fe3O4/Pyr have some advantages such as i) capability of application for various halides containing different functional groups, ii) ease of purification of final product and iii) simple work-up.

Ullmann‐Ma Reaction: Development, Scope and Applications in Organic Synthesis†

SummaryCopper‐catalyzed cross‐couplings of aryl halides and nucleophiles, traditionally called Ullmann‐type coupling reactions, were initially reported by Ullmann et al. from 1901—1929. A seminal report in 1998 by Ma et al. from Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences revealed an accelerating effect caused by amino acids, which brought Ullmann‐type coupling reactions into a ligand‐accelerating era. From 1999 to the first 10 years of 2000s, the first‐generation ligands were developed by many researchers and promoted Ullmann‐type coupling reactions of aryl iodides and bromides under relatively mild conditions. Amino acid ligands, developed by Ma and coworkers, are one class of the most important first‐generation ligands. In the second 10 years of 2000s, Ma et al. led the discovery of second‐generation ligands for copper‐catalyzed cross‐coupling reactions. Two great breakthroughs have been realized by using second‐generation oxalic diamide and related amide ligands, with aryl chlorides as general coupling partner and with low catalyst loadings. Now copper‐catalyzed cross coupling reactions of aryl halides and nucleophiles with amino acids or oxalic diamides and related amides as ligands are recognized as Ullmann‐Ma reactions and have found extensive applications in organic synthesis.

Binuclear Palladium Complex Immobilized on Mesoporous SBA-16: Efficient Heterogeneous Catalyst for the Carbonylative Suzuki Coupling Reaction of Aryl Iodides and Arylboronic Acids Using Cr(CO)6 as Carbonyl Source

In this study, a binuclear palladium complex immobilized on the organo-functionalized SBA-16 was prepared and structurally characterized by routine techniques. Characterizations indicated that the mesostructure of SBA-16 was maintained after the immobilization of palladium complex. Then, the prepared nanomaterial was applied as a heterogeneous catalyst in the carbonylative Suzuki coupling reaction of aryl iodides with arylboronic acids using Cr(CO)6 as carbonyl source. The catalyst was efficiently promoted the coupling reactions of various aryl iodides and arylboronic acids to give the corresponding diaryl ketones in excellent yields. Moreover, the catalyst was readily recovered by filtration and could be reused for seven cycles without losing its structural integrity and catalytic activity.

The synthesis of unnatural α-alkyl- and α-aryl-substituted serine derivatives.

The synthesis of α-aryl- and α-alkyl-substituted serine derivatives via [3,3]-sigmatropic rearrangement of allyl carbamates as a key step is reported. Allyl carbamates were obtained from the corresponding allyl alcohols. The former were prepared through three approaches. Aryl-substituted ones were synthesized via the Stille coupling reaction of aryl iodides with enantiomerically enriched vinyl stannanes. Conversely, alkyl-substituted allyl alcohols were prepared by an analogous strategy involving the Negishi coupling reaction of enantiomerically enriched vinyl iodides or by enzymatic kineric resolution of the corresponding racemic alcohols.

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids.

It was demonstrated that the γ-valerolactone-based ionic liquid, tetrabutylphosphonium 4-ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to excellent yields (72–99%) and purity (>98%). These results represent an example which proves that biomass-derived safer solvents can be utilized efficiently in common, industrially important transformations exhibiting higher chemical and environmental efficiency.

Copper-Catalyzed Three-Component Coupling Reaction of Aryl Iodides, a Disilathiane, and Alkyl Benzoates Leading to a One-Pot Synthesis of Alkyl Aryl Sulfides

A copper-catalyzed three-component coupling reaction of aryl iodides, hexamethyldisilathiane and alkyl benzoates leading to alkyl aryl sulfides has been demonstrated. A disilathiane acted as both a sulfur source and a promoter of the sulfidation, and the alkyl moiety of the alkyl benzoate was effectively introduced on one side of the sulfide. Moreover, we found that the protocol can be expanded to the preparation of ethyl phenyl selenide with diphenyl diselenide.

Oxidative Aminoarylselenation of Maleimides via Copper-Catalyzed Four-Component Cross-Coupling.

The first example of copper-catalyzed four-component coupling reaction of aryl iodides, Se powder, secondary amines, and maleimides is developed. This reaction provides an efficient and concise route to access aminoarylselenated maleimides via double C-Se bonds and C-N bond formation. The appealing features of this transformation are the use of Se powder as a selenating reagent, a green catalytic system, a wide range of substrate scope, and late-stage selenation of bioactive compounds.