Cross-coupling Reaction Of Aryl Iodides Research Articles

Water-Dispersible, Magnetically Recyclable Heterogeneous Cobalt Catalyst for C-C and C-N Cross-Coupling Reactions in Aqueous Media.

A cobalt catalyst supported on an iron oxide core, denoted as γ-Fe2O3@PEG@THMAM-Co, has been prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray mapping, thermogravimetry differential thermogravimetry, vibrating sample magnetometry, and inductively coupled plasma. Polyhydroxy end groups in the shell make the catalyst particles dispersible in water, allowing Hiyama, Suzuki, and C-N cross-coupling reactions of aryl iodides and bromides. The catalyst could be recovered by magnetic decantation and reused for at least five successive runs with a negligent decrease in its activity or changes in its morphology. Water as a solvent without requiring additives, surfactants, or organic co-solvents, as well as an abundant and low-cost cobalt catalyst combined with facile recovery, low leaching, and scalability, provides an environmentally and economically attractive alternative to established palladium-catalyzed C-C and C-N coupling reactions.

Gold-Catalyzed C-N Cross-Coupling Reactions of Aryl Iodides with Alkyl Nitriles or Silver Cyanate.

We have gold-catalyzed C-N cross-couplings of aryl iodides with aliphatic nitriles. Although nitriles are usually challenging nitrogen cross-coupling partners, they could be activated by base-mediated deprotonation and isomerization. The method utilizes widely available substrates in moderate to good yields to provide various N-aryl compounds. In addition, a similar strategy could be extended to the cross-couplings of aryl iodides with silver cyanate. The protocol features high humidity/air tolerance and works inter- and intramolecularly.

Gold-Catalyzed C-O Cross-Coupling Reactions of Aryl Iodides with Silver Carboxylates.

We have developed a C-O cross-coupling reaction of (hetero)aryl iodides with silver carboxylates via a AuI/AuIII catalytic cycle. The transformation featured exclusive chemoselectivity and moisture/air insensitivity. Aromatic and aliphatic (including primary, secondary, and tertiary) silver carboxylates are all suitable substrates. Moreover, this protocol worked well intermolecularly and intramolecularly. Most importantly, good yields were obtained regardless of the substrates' electronic effect and steric hindrance.

Gold Catalysis: A New Contender for Cross-Coupling Reactions with Aryl Halides

Cross-coupling reactions of aryl halides catalyzed by transition metals such as Pd, Ni, Cu etc have shown to be effective tools for the generation of carbon–carbon and carbon–heteroatom bonds. However, because of the difficulties associated with the oxidative addition of organohalides or pseudohalides on gold complexes, such cross- coupling reactions are non-trivial in gold catalysis. Recent research revealed that gold- catalyzed cross-coupling reactions of aryl iodides are possible and the current article shall briefly discuss the state-of-the-art in the field.

Ligand-Enabled Gold-Catalyzed C(sp2)–O Cross-Coupling Reactions

Reported herein is a ligand-enabled gold-catalyzed C(sp2)–O cross-coupling reaction of aryl iodides and aliphatic alcohols. The synthesis of a variety of aryl alkyl ethers including complex biomolecules and various medicinally relevant motifs has been achieved to demonstrate the usefulness of the method. The importance of gold catalysis has been highlighted by overcoming the selectivity issues that are in general observed for C–O cross-coupling reactions when other transition metals are used as catalysts.

Palladium Supported on Porous Organic Polymer as Heterogeneous and Recyclable Catalyst for Cross Coupling Reaction

Palladium immobilized on an amide and ether functionalized porous organic polymer (Pd@AEPOP) is reported to be an effective heterogeneous catalyst for the Heck cross-coupling reaction of aryl iodides with styrene for the synthesis of diphenylethene derivatives. Excellent yields can be obtained using a 0.8 mol% Pd catalyst loading under the optimized reaction condition. The heterogeneous Pd@AEPOP catalyst can also be applied on the Suzuki reaction and the reduction of nitroarene.

Zinc (II) complex immobilized on the surface of magnetic nanoparticles modified with phenanthroline: A novel and efficient nanomagnetic reusable catalyst for cross-coupling reaction of aryl iodides with terminal aromatic alkynes

A novel and green nanomagnetic zinc catalyst were fabricated via the immobilization of zinc (II) complex on the surface of magnetic nanoparticles modified with phenanthroline (MNPs-Phen-Zn(II)). The structure of MNPs-Phen-Zn(II) nanomaterial was characterized by a series of spectroscopic techniques including FT-IR spectroscopy, SEM, TEM, EDX, XRD, VSM, and ICP-OES. The resulting zinc nanomagnetic catalyst was shown high catalytic activity for the synthesis of disubstituted alkynes via C(sp2)–C(sp) cross-coupling reactions of alkynes with aryl iodides under eco-friendly conditions. To the best of our knowledge, it is the first report on the utilization of zinc nanomagnetic catalyst for the Sonogashira type cross-coupling reaction of alkynes with aryl iodides in the absence of added Pd and Cu sources. The simple preparation of the catalyst from commercially available materials, excellent chemoselectivity, easy separation of products, and straightforward recovery and reusability of the catalyst with unaltered activity make our procedure a green and practical method.

Ligand-Enabled Gold-Catalyzed C(sp2)-S Cross-Coupling Reactions.

Herein we report C(sp2)-S cross-coupling reactions of aryl iodides and arylsulfonyl hydrazides under ligand-enabled, Au(I)/Au(III) redox catalysis. This strategy operates under mild reaction conditions, requires no prefunctionalized aryl coupling partner, and works across several aryl iodides. The utility of this protocol is highlighted through the synthesis of various medicinally relevant biaryl sulfones. The reaction mechanism is supported with control experiments, mass spectrometry, and NMR studies.

New Nickel-Based Catalytic System with Pincer Pyrrole-Functionalized N-Heterocyclic Carbene as Ligand for Suzuki-Miyaura Cross-Coupling Reactions

A new catalytic system with Ni(NO3)2·6H2O as the catalyst and a pincer pyrrole-functionalized N-heterocyclic carbene as the ligand was employed in the Suzuki-Miyaura cross-coupling reactions of aryl iodides with arylboronic acids. With 5 mol% catalyst, the catalytic reactions proceeded at 160 °C, giving coupling products in isolated yields of up to 94% in short reaction times (1-4 h). The system worked efficiently with aryl iodides bearing electron-donating or electron-withdrawing groups and arylboronic acids with electron-donating groups. Steric effects were observed for both aryl iodides and arylboronic acids. It is proposed that the reactions underwent a Ni(I)/Ni(III) catalytic cycle.

-Proline N-oxide dihydrazides as an efficient ligand for cross-coupling reactions of aryl iodides and bromides with amines and phenols

A novel catalytic system based on l -proline N-oxide/CuI was developed and applied to the cross-coupling reactions of various N- and O- nucleophilic reagents with aryl iodides and bromides. This strategy featured in the employment of an l -proline derived dihydrazides N-oxide compound as the superior supporting ligand. By using this protocol, a variety of products, including N-arylimidazoles, N-arylpyrazoles, N-arylpyrroles, N-arylamines, and aryl ethers, were synthesized with up to 99% yield. • A novel l -proline based N-oxide ligand has been designed and synthesized. • The developed ligand performed well in copper catalyzed Ullmann-type cross-coupling reactions. • This ligand showed high compatibility in both C–N and C–O bond formation reactions. • A broad substrate scope with respect to both coupling components worked efficiently in high yields.

The role of CuI in the siloxane-mediated Pd-catalyzed cross-coupling reactions of aryl iodides with aryl lithium reagents

Experiments indicate that a catalytic amount of CuI plays an important role in the siloxane-mediated Pd-catalyzed cross-coupling reactions with the direct use of organolithium reagents. Addition of organolithium to the siloxane transfer agent generates an organosilicon intermediate. DFT calculations indicate that CuI initially accelerates the Si-Pd(II) transmetalation of the organosilicon intermediate by the formation of CuI2−. Subsequently, CuI2− works as a shuttle between the Si-Cu(I) and Cu(I)-Pd(II) transmetalation processes.

Ligand-Enabled Gold-Catalyzed C(sp2)-N Cross-Coupling Reactions of Aryl Iodides with Amines.

The first example of ancillary (P,N)-ligand-enabled gold-catalyzed C-N cross-coupling reactions of aryl iodides with amines is reported. The high generality of the reaction in de novo synthesis, late-stage modifications, and cascade processes to access functionalized indolinones and carbazoles underscores the synthetic potential of the presented strategy. Monitoring the reaction with ESI-HRMS and NMR provided strong evidence for the in situ formation of putative high valent Au(III) intermediates.

Pd-Catalyzed Alkyne Insertion/C-H Activation/[4 + 2] Carboannulation of Alkenes to the Synthesis of Polycyclics.

An unprecedented Pd-catalyzed alkyne insertion/C-H activation/intramolecular [4 + 2] carboannulation of alkenes has been reported. In this transformation, the C-H activation was triggered by an in situ generated alkenylpalladium species via the Pd-catalyzed cross-coupling reaction of aryl iodides and alkynes. Subsequently, the resulting five-membered C, C-palladacycle intermediates were added across the alkenes, providing a unique approach to access diversified polycyclics in good efficiency. Two new rings and three C-C bonds were formed in one pot.

A practical synthesis of unsymmetrical triarylphosphines by heterogeneous palladium(0)-catalyzed cross-coupling of aryl iodides with diphenylphosphine

The heterogeneous cross-coupling reaction of aryl iodides with diphenylphosphine was achieved in DMAc at 130 °C in the presence of 1.0 mol% of MCM-41-supported tridentate nitrogen palladium(0) complex [MCM-41-3N-Pd(0)] with KOAc as base, yielding a variety of unsymmetrical triarylphosphines in good to excellent yields. The turnover frequency (TOF) of the catalyst can reach 30.67 h−1. This new heterogeneous palladium(0) catalyst could easily be prepared by a simple procedure from commercially readily available reagents, and exhibited the same catalytic activity as homogeneous Pd(OAc)2 or Pd(PPh3)4, and could be recovered by filtration of the reaction solution and recycled at least seven times without significant loss of catalytic activity.

A Highly Efficient CuCl2-Catalyzed C–S Coupling of Aryl Iodides with Tetraalkylthiuram Disulfides: Synthesis of Aryl Dithiocarbamates

A highly efficient copper(II)-catalyzed C–S cross-coupling reaction of aryl iodides with tetraalkylthiuram disulfides was developed. With only 1 mol% of CuCl2 as catalyst, zinc powder as reductant, and K2CO3 as base, aryl iodides reacted with tetraalkylthiuram disulfides in DMSO furnishing the corresponding aryl dithiocarbamates in good to excellent yields. This protocol is an improvement of previous work, it features convenient performance, low addition of catalyst, no requirement for any ligand, and provides good yields. The method has a broad substrate scope and uses cheap and readily available starting materials.

Catalytic cross-coupling reaction of aryl iodides with triarylbismuths by an N-heterocyclic carbene-PdCl2 based on benzo-9-crown-3 catalyst at room temperature

We have developed the N-heterocyclic carbene ligand/PdCl2 catalyst for CC coupling reaction of aryl iodides and organobismuths at room temperature. The established catalytic system exhibited high cross-coupling reactivity between a variety of orgnobismuths and aryl iodides in the presence of K2CO3 as base in NMP or DMSO at room temperature. The simple and efficient transformation can tolerate either electron-withdrawing or electron-donating functional groups. It was notably found that both aryl bromide and aryl chloride generated moderate to good yields of the corresponding biphenyl products using 5mol% of PPh3/ligand 5 (1:1) as catalyst.

A phosphine-free, atom-efficient cross-coupling of aryl iodides with triarylindiums or trialkynylindiums catalyzed by immobilization of palladium(0) in MCM-41

The first phosphine-free heterogeneous atom-efficient cross-coupling reaction of aryl iodides with triarylindiums or trialkynylindiums was achieved in THF at 68 °C by using 1 mol% of MCM-41-immobilized palladium(0)-Schiff base complex [MCM-41-N,N-Pd(0)] as catalyst, yielding a variety of unsymmetrical biaryls and arylalkynes in good to excellent yields. The heterogeneous palladium(0) catalyst could easily be prepared via a simple procedure from commercially readily available reagents, and recovered by filtration of the reaction solution and recycled at least 10 times without significant loss of activity.

Synthesis of 3-Aryl-2-pyrones by Palladium-Catalyzed Cross-Coupling of Aryl Iodides with Cyclic Vinyldiazo Ester.

A palladium-catalyzed cross-coupling reaction of aryl iodides with cyclic vinyldiazo ester was developed. The reaction provides various 3-aryl-2-pyrones in good yields with high functional group tolerance. The synthetic application of the resulting 3-aryl-2-pyrones as the diene component in a Diels-Alder reaction was also described.

Bench-Stable and Recoverable Palladium(I) Dimer as an Efficient Catalyst for Heck Cross-Coupling

The application of air- and moisture-stable dinuclear palladium(I) complex [Pd(μ-I)(P<i>t</i>-Bu₃)]₂ as an efficient catalyst for the Heck cross-coupling reaction of aryl iodides and bromides with acrylates and styrenes is described. The developed protocol is robust and operationally simple and shows a high functional-group tolerance. The employed palladium(I) dimer catalyst is highly robust under these nucleophilic as well as elevated-temperature conditions, allowing its recovery after reaction completion and recycling.

Palladium-Catalyzed Negishi Cross-Coupling Reaction of Aryl Halides with (Difluoromethyl)zinc Reagent.

The palladium-catalyzed Negishi cross-coupling reaction of aryl iodides and bromides with (difluoromethyl)zinc reagent bearing a diamine such as TMEDA is achieved to provide the difluoromethylated aromatic compounds in good to excellent yields. The advantages of (difluoromethyl)zinc reagent are that (1) the derivatives, which possess different stability and reactivity, can be readily prepared via ligand screening and (2) transmetalation of a difluoromethyl group from the zinc reagent to palladium catalyst efficiently proceeds without an activator.