A general rhodium-catalyzed cross-coupling reaction of thiols with aryl iodides

The general procedure for the rhodium-catalyzed cross-coupling of thiols with aryl iodides is described. The catalytic system consists of 5 mol % of [RhCl(cod)]₂ and 10 mol % of PPh₃ as a ligand. A variety of aryl iodides reacted with thiols, giving aryl thioethers in good to excellent yields. It is important to note that the deactivated aryl iodides such as 4-iodoanisole is worked smoothly to provide the corresponding aryl thioethers in excellent yields. Functional groups such as free-amines, chloro, are all tolerated under the employed reaction conditions.     

Copper-catalyzed direct preparation of diaryl sulfides from aryl iodides using potassium thiocyanate as a sulfur transfer reagent

A method for direct preparation of diaryl sulfides from aryl iodides using potassium thiocyanate as a sulfur-transfer agent is reported. A catalyst system comprising of a simple copper salt, tetrabutylammonium bromide as a phase-transfer agent and water as the solvent is used. Microwave heating at 200 °C for 60 min allows for the conversion of a range of aryl iodides to the corresponding diaryl sulfides.     

Unexpectedly ligand-free copper-catalyzed C–S cross-coupling of benzothiazole with aryl iodides in aqueous solution

A novel synthetic protocol for 2-aminophenyl sulfide derivatives via the reactions of benzothiazole with aryl iodides was reported for the first time. The reactions were catalyzed by CuCl with tetrabutylammonium hydroxide as the base and water as the solvent without ligand at 50 °C or room temperature. A variety of aryl iodides underwent the C–S cross-coupling reaction with benzothiazole to afford smoothly the corresponding products in excellent yield.     

NHC‐Pd complex‐catalyzed double carbonylation of aryl iodides with secondary amines to α‐keto amides

A series of palladium–NHC compounds were prepared and their catalytic activity in the double carbonylation of aryl iodides to synthesize α‐keto amides were examined. Palladium complexes bearing mixed NHC–phosphine exhibited high efficiency for the double carbonylation reaction. The effects of different solvents, base, temperature, carbon monoxide (CO), pressure, various amine and aryl iodides were investigated. Both electron‐rich and electron‐deficient aryl iodides afforded the corresponding substituted α‐keto amides in moderate to good yields. A possible mechanism was also proposed. Copyright © 2013 John Wiley & Sons, Ltd.     

Convenient copper- and solvent-free Sonogashira-type alkynylation of aryl iodides and bromides using Pd EnCat™

A straightforward methodology is described for the copper- and solvent-free alkynylations of aryl iodides and bromides using 0.1-0.01 mol % of Pd as Pd EnCat™ 40 or TPP30. High yielding reactions can be achieved under aerobic conditions for a variety of activated and deactivated aryl iodides; a few examples with aryl bromides are also described. Microwave irradiation is able to enhance yields and rates of these reactions.     

Copper-catalyzed cross-coupling of sulfonamides with aryl iodides and bromides facilitated by amino acid ligands

A highly general, convenient, and inexpensive catalyst system was developed for the N-arylation of sulfonamides with aryl iodides or bromides by using 5-20 mol % of CuI as catalyst, 20 mol % of N-methylglycine (for aryl iodides) or N,N-dimethylglycine (for aryl bromides) as ligand, and K₃PO₄ as base.     

CuI/PPh3‐catalyzed Sonogashira coupling reaction of aryl iodides with terminal alkynes in water in the absence of palladium

The Sonogashira cross‐coupling of aryl iodides with terminal alkynes catalyzed by a simple and inexpensive catalyst system of CuI/PPh₃ in water as the sole solvent has been reported. In the presence of CuI/PPh₃, with KOH used as a base, a number of aryl iodides were treated with alkynes to afford the corresponding products in moderate to excellent yields. Copyright © 2008 John Wiley & Sons, Ltd.     

Efficient ligand-free copper-catalyzed C-S cross-coupling of thiols with aryl iodides using KF/Al2O3 as base

We report a mild, convenient, environmentally friendly, and ligand-free synthetic protocol for the cross-coupling reaction of aryl iodides and thiols using 10 mol % CuI with KF/Al₂O₃ as the base, in DMF at 110 °C. Using this protocol, we have shown that a variety of aryl sulfides can be synthesized in excellent yields from readily available iodides and thiols.     

Palladium-catalyzed Mizoroki-Heck reaction of allyl aryl ethers with aryl iodides using phosphine-free hydrazone ligands

Palladium-catalyzed Mizoroki-Heck reaction of allyl aryl ethers with aryl iodides gave aryl cinnamyl ethers using a catalytic amount of Pd(OAc)₂ in DMF at 50 °C with phosphine-free hydrazone as a ligand in good yields.     

A copper- and amine-free Sonogashira coupling reaction promoted by a ferrocene-based phosphinimine-phosphine ligand at low catalyst loading

A palladium(II) complex containing a ferrocene-based phosphinimine-phosphine ligand was applied to the amine- and copper-free Sonogashira coupling of aryl iodides and aryl bromides with terminal alkynes using 1 equiv of tetrabutylammonium acetate as an activator. The corresponding disubstituted alkynes were obtained in high yields and TONs using 0.1 mol % Pd-catalyst.     

A general method for the formation of diaryl selenides using copper(I) catalysts

We report a mild, palladium-free synthetic protocol for the cross coupling reaction of aryl iodides and phenyl selenol using 10 mol% CuI/neocuproine, NaOt-Bu or K₂CO₃ as base, in toluene, at 110°C. Using this protocol, we show that a variety of diaryl selenides can be synthesized in good yields from commercially available aryl iodides.     

Efficient copper-catalyzed coupling of aryl iodides and thiobenzoic acid

A highly efficient copper-catalyzed coupling reaction of aryl iodides and thiobenzoic acid, using 10 mol % of copper iodide, 20 mol % of 1,10-phenanthroline, and ⁱPr₂NEt in toluene, was developed. This methodology is applicable to a variety of aryl iodides.     

Active palladium catalyst supported by bulky diimine ligand catalyzed Suzuki–Miyaura coupling reaction in water under phosphane‐free and low catalyst loading conditions

A new catalytic system based on palladium and bulky diimine ligand for Suzuki–Miyaura coupling reaction of aryl iodides, bromides and chlorides in neat water is described. The desired biphenyl products were obtained in high to excellent yields for aryl iodides and bromides in the presence of low catalyst loading. Air‐stable catalyst has been recycled for the reaction of iodobenzene with phenylboronic acid for five consecutive runs. Copyright © 2014 John Wiley & Sons, Ltd.     

Improved synthesis of phenylethylamine derivatives by Negishi cross-coupling reactions

Trifluoroacetamido-protected β-aminoalkylzinc iodides undergo Negishi cross-coupling reaction with aryl iodides in moderate to excellent yields (42-84%) based on the corresponding trifluoroacetamido-protected β-aminoalkyl iodides, employing a catalyst prepared in situ from Pd₂(dba)₃ and SPhos (1:2 M ratio). In general, meta- and para-substituted aryl iodides give good results using relatively low levels of catalyst [0.25 mol % Pd₂(dba)₃], but more hindered ortho-substituted examples require higher catalyst loadings. The preparation of trifluoroacetamido-protected β-aminoalkyl iodides is straightforward, and the intermediates are significantly more stable than the corresponding Boc-protected derivatives.     

Microwave-enhanced and ligand-free copper-catalyzed cyanation of aryl halides with K4[Fe(CN)6] in water

Copper-catalyzed cyanation of aryl halides was improved to be more economical and environmentally friendly by using water as the solvent and ligand-free Cu(OAc)₂·H₂O as the catalyst under microwave heating. The suggested methodology was applicable to a wide range of substrates including aryl iodides and activated aryl bromides.     

Palladium-catalyzed cyanation of aryl halides using K4[Fe(CN)6] as cyanide source, water as solvent, and microwave heating

A methodology for the cyanation of aryl iodides and activated aryl bromides is reported using water as the solvent and K₄[Fe(CN)₆] as the cyanide source. Reactions are complete within 20 min.     

Cu(OAc)2·H2O-catalyzed N-arylation of nitrogen-containing heterocycles

In the absence of any additional ligands, the efficient N-arylation of nitrogen-containing heterocycles with aryl iodides catalyzed by relative low catalyst amount of Cu(OAc)₂·H₂O was developed. This simple catalytic system is involved in the C-N cross-coupling reaction and works for a variety of pyrazole, pyrrole, imidazole, triazole, indole, benzoimidazole, benzotriazole, carbazole, and anilines as well as aryl iodides with different electronic properties. Highly efficient copper(II)-catalyzed N-arylation protocol was established.     

CuI/8‐Hydroxyquinalidine Promoted N‐Arylation of Indole and Azoles

An efficient catalytic system of CuI/8‐hydroxyquinalidine was developed for the coupling of aryl iodides and indole as well as some azoles. The reaction could be carried out at 90°C under the condition of relatively low catalyst loading, affording various N‐arylindoles and N‐aryl azoles in good yields. The functionalized and hindered aryl iodides were suitable substrates for this transformation.     

Phosphine-free Pd-salen complexes as efficient and inexpensive catalysts for Heck and Suzuki reactions under aerobic conditions

Phosphine-free palladium-salen complexes, N,N′-bis(salicylidene)-ethylenediamino-palladium and N,N′-bis(salicylidene)-1,2-phenylenediamino palladium, are found to be highly active catalysts for the Heck olefination of aryl iodides and Suzuki reaction of aryl iodides and bromides giving excellent yields (70-90%) of products under aerobic conditions, in short reaction times (10-60 min).     

Visible-light-induced cross-coupling of aryl iodides with hydrazones via an EDA-complex

A visible-light-induced, transition-metal and photosensitizer-free cross-coupling of aryl iodides with hydrazones was developed. In this strategy, hydrazones were used as alternatives to organometallic reagents, in the absence of a transition metal or an external photosensitizer, making this cross-coupling mild and green. The protocol was compatible with a variety of functionalities, including methyl, methoxy, trifluoromethyl, halogen, and heteroaromatic rings. Mechanistic investigations showed that the association of the hydrazone anion with aryl halides formed an electron donor–acceptor complex, which when excited with visible light generated an aryl radical via single-electron transfer.

Visible-light-induced catalyst-free cross-coupling of aryl iodides with hydrazones via single-electron-transfer was reported. The mechanistic investigations showed that the association of hydrazone anion with aryl iodides formed an EDA complex.