Amine‐bridged bis(phenol) ligands for efficient Pd‐catalyzed aqueous C‐C coupling reactions

The influence of ring size ( 5 or 6 ), chain length ( 1 , 2 or 3 ) and bulkiness of N‐aryl substituents in amine‐bridged bis(phenol) ligands ( 1 , 2 , 3 ) on palladium‐catalyzed aqueous C‐C coupling reactions were revealed. The homocoupling of arylboronic acid can be completed in neat water with the aid of a catalytic amount of p‐toluenesulfonyl chloride (TsCl) in a very short time under anaerobic or aerobic conditions. Interestingly, the same catalytic system was efficient for Suzuki–Miyaura reaction in aqueous acetone under aerobic conditions in the absence of TsCl. The crystal structures of ligand 1 and three unsymmetrical fluorine‐substituted biaryl derivatives were also reported. Copyright © 2013 John Wiley & Sons, Ltd.     

Bis(imino)pyridine palladium(II) complexes as efficient catalysts for the Suzuki–Miyaura reaction in water

Bis(imino)pyridine palladium(II) complexes 3 and 4 of type [PdCl(L)PF₆] are found to be efficient catalysts for Suzuki–Miyaura reactions of aryl halides and arylboronic acids. The reactions proceed smoothly to generate the corresponding biaryl compounds in moderate to excellent yields. The synthesis of various fluorinated biphenyl derivatives was successfully achieved by the complex 4 catalyzed the Suzuki–Miyaura reaction in the presence of surfactants bearing a long alkyl chain. Copyright © 2009 John Wiley & Sons, Ltd.     

Alcoholic solvent‐assisted ligand‐free room temperature Suzuki–Miyaura cross‐coupling reaction

We have observed the enhancing effect of alcoholic solvents in palladium‐catalysed ligand‐free Suzuki–Miyaura reactions. No extra additives or ligands are required for the Suzuki–Miyaura reaction of aryl bromides with arylboronic acids when we carried out the reaction in alcoholic or aqueous alcoholic solvents. Moreover, ethanol or aqueous ethanol is found to be a very good solvent for the Suzuki–Miyaura reaction involving electronically diverse aryl bromides and arylboronic acids under mild and ligand‐free conditions with low catalyst loading. It is observed from Hg(0) poisoning tests that the in situ generated palladium(0) species is the actual catalytic species for the reaction. Copyright © 2015 John Wiley & Sons, Ltd.     

氯化钯在氟化四丁基铵中当场生成纳米钯：一种高效、可回收的催化体系，在无配体和无溶剂条件下催化Suzuki-Miyaura反应

氯化钯在氟化四丁基铵中当场生成纳米钯,该钯催化剂在Suzuki-Miyaura交叉偶联反应中显示很高的催化效率。在氯化钯和氟化四丁基铵存在下,许多芳基卤代烃可以顺利与芳基硼酸发生偶联反应,得到中等到高的产率。此外,在Suzuki-Miyaura偶联反应中该氯化钯/氟化四丁基铵催化体系可以回收重复使用多次,并且芳基溴代烃可以在15-60分钟内反应完全。值得指出的是,该反应是在无溶剂、无配体和催化体系可回收重复使用的条件下进行的。这和无配体条件下TBAB中钯催化卤代芳烃与芳基硼酸的Suzuki-Miyaura交叉偶联反应方法。该氯化钯/氟化四丁基铵催化反应的反应机理也进行了讨论。     

18‐Crown‐6 promoting Pd/C‐catalyzed cross‐coupling reaction of aryl bromides and arylboronic acids in aqueous media

Pd/C‐catalyzed Suzuki–Miyaura cross‐coupling between aryl bromides and arylboronic acids in 50% methanol aqueous solution proceeded smoothly in the presence of 18‐crown‐6. Various aryl bromides bearing electron‐withdrawing groups and electron‐donating groups coupled with arylboronic acid in high yields. In addition, the catalyst could be recycled five times without loss of activity. Copyright © 2012 John Wiley & Sons, Ltd.     

Metallomicelles of palladium(II) complexes as efficient catalysts for the Suzuki–Miyaura reaction in neat water

Metallomicelles of palladium(II) complex 4 are found to be an efficient catalyst for Suzuki–Miyaura reactions of aryl bromides substituted with a long alkyl chain and arylboronic acids at 80 °C in neat water. The reactions proceed smoothly to generate the corresponding biaryl compounds in moderate to excellent yields. Various biphenyl derivatives were successfully obtained by complex 4 catalysis of the Suzuki–Miyaura reactions in the absence of any surfactants in neat water. Copyright © 2013 John Wiley & Sons, Ltd.     

Efficient pyridylbenzamidine ligands for palladium‐catalyzed Suzuki–Miyaura reaction

A series of pyridylbenzamidine ligands were applied in palladium‐catalyzed Suzuki–Miyaura reactions and the effect of ligand on catalytic properties was evaluated. Under the optimization conditions, the bulky and electron‐donating nitrogen donor ligands were successfully used to catalyze the reaction of a variety of aryl bromides and aryl chlorides with arylboronic acid, giving the desired products in moderate to high yields. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis,characterization and catalytic activity in Suzuki–Miyaura coupling of palladacycle complexes with n‐butyl‐substituted N‐heterocyclic carbene ligands

A series of monomeric palladacycle complexes bearing n‐butyl‐substituted N‐heterocyclic carbenes, namely [Pd(NHC)X(dmba)] (dmba: dimethylbenzylamine and [Pd(NHC)X(ppy)]; NHC: 1‐n‐butyl‐3‐substituted benzylimidazol‐2‐ylidene; ppy: 2‐phenylpyridine), were prepared either by transmetallation from the corresponding silver carbene complexes or by the reaction of the corresponding acetate‐bridged palladacycle dimer with N‐heterocyclic carbene ligands in high yields. The palladium(II) complexes were characterized using elemental analyses, APCI‐MS, ¹H NMR and ¹³C NMR spectroscopies. These complexes are efficient in the Suzuki–Miyaura coupling reaction between phenylboronic acid and aryl bromides.     

Suzuki–Miyaura reactions promoted by a PdCl2/sulfonate‐tagged phenanthroline precatalyst in water

This work reports Suzuki–Miyaura cross‐coupling reactions of arylboronic acid with aryl halide or aryl dibromide mediated by PdCl₂ (0.05 mol%) and sodium 4‐(1H‐imidazo[4,5‐f][1,10]phenanthrolin‐1‐yl)butane‐1‐sulfonate (0.05 mol%) at 100 °C in water. The corresponding cross‐coupling products were obtained in good to excellent yields. The catalytic system was recovered from the organic products by extraction with ether and the residual aqueous catalyst phase showed high activity after reuse of at least four cycles. Copyright © 2014 John Wiley & Sons, Ltd.     

An Efficient Palladium and Bis(2‐pyridylmethyl)amine‐based System for Suzuki‐Miyaura Cross‐Coupling under Aqueous and Aerobic Condition

A novel PdCl₂/bis(2‐pyridylmethyl)amine‐based ligand ( 1 ) catalytic system, which is water‐soluble and air‐stable, has been successfully synthesized and applied for Suzuki‐Miyaura cross‐coupling reaction. In the presence of catalytic amount of PdCl₂/ 1 system, arylboronic acids can couple with a wide range of aryl halides, including aryl bromides and aryl chlorides. The reactions proceed under mild conditions to give excellent yields, and a wide range of functionalities is tolerated.     

A highly active palladium(II)–bis(oxazoline) catalyst for Suzuki–Miyaura,Mizoroki–Heck and sonogashira coupling reactions in aqueous dimethylformamide

An efficient catalytic system based on a new palladium–bis(oxazoline) ( Pd-BOX-1 ) complex has been developed. The complex Pd-BOX-1 adopts a legless chair‐type structure where the distorted square planar [PdN₂Cl₂] moiety and the benzene ring spacer represent the seat and the chair back, respectively. The catalytic activity of Pd-BOX-1 has been investigated in dimethylformamide–water under aerobic and mild conditions in Suzuki–Miyaura coupling reactions of arylboronic acids with aryl iodides, aryl bromides and aryl chlorides, Mizoroki–Heck coupling reactions of aryl halides with styrene derivatives, and Sonogashira coupling reactions of aryl halides with terminal alkynes. A wide range of functional groups as substituents on the arylboronic acids and aryl halides were considered. Pd-BOX-1 demonstrates exceptional air and moisture stability. Of note, the catalyst system based on Pd-BOX-1 shows high recycling ability in Suzuki–Miyaura coupling reactions in dimethylformamide–water without any loss in catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,characterization and catalytic activity of Pd(II) complexes with N‐allyl functionalized imidazol‐2‐ylidenes in Suzuki–Miyaura reaction

A series of Pd–N‐heterocyclic carbene (Pd–NHC) complexes were synthesized and characterized by elemental analysis and spectroscopic methods. In addition, the molecular structures of 3c and 4c were determined by X‐ray diffraction studies. Finally, the performance of complexes 3 and 5 were studied on Suzuki–Miyaura reactions of phenylboronic acid with aryl bromides. Copyright © 2014 John Wiley & Sons, Ltd.     

Palladium nanoparticles‐decorated triethanolammonium chloride ionic liquid‐modified TiO2 nanoparticles (TiO2/IL‐Pd): A highly active and recoverable catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous medium

In this work, an easily obtained procedure was successfully implemented to prepare novel palladium nanoparticles decorated on triethanolammonium chloride ionic liquid‐functionalized TiO₂ nanoparticles [TiO₂/IL‐Pd]. Different methods were carried out for characterizations of the synthesized nanocatalyst (HR‐TEM, XPS, XRD, FE‐SEM, EDX, FT‐IR and ICP). TiO₂/IL‐Pd indicated good catalytic activity for the Suzuki–Miyaura cross‐coupling reaction of arylboronic acid with different aryl halides in aqueous media at ambient temperature. The recycled catalyst was investigated with ICP to amount of Pd leaching after 6 times that had diminished slightly, Thus, was confirmed that the nanocatalyst has a good sustainability for C–C Suzuki–Miyaura coupling reaction. The catalyst can be conveniently separated by filtration of the reaction mixture and reused for 6 times without significant loss of its activity. It supplies an environmentally benign alternative path to the existing protocols for the Suzuki–Miyaura reaction.     

Synthesis,characterization, and reactivity of palladium(II) complexes containing piperidoimidazolin‐2‐ylidene

A series of Pd–N‐heterocyclic carbene (Pd‐NHC) complexes with pyrazine ( 1 ) or pyridine ( 2 ) and NHC ( 3 ) were synthesized and characterized by elemental analysis and spectroscopic methods. In addition, the molecular structure of 3 was determined by X‐ray diffraction studies. The effects of these ligands on catalyst activation and the performance of complexes 1 , 2 , 3 were studied on Suzuki–Miyaura reactions of phenylboronic acid with aryl chlorides. Finally, we demonstrated that complex 1 is very adept at re‐forming the Kumada–Tamao–Corriu cross‐coupling reaction. Copyright © 2013 John Wiley & Sons, Ltd.     

Acetanilide palladacycle: an efficient catalyst for room‐temperature Suzuki–Miyaura cross‐coupling reaction

The catalytic activity of three acetanilide palladacycles derived from easily accessible and commercially available acetanilide derivatives, viz. N‐phenylacetamide ( L1 ), N‐(4‐chlorophenyl)acetamide ( L2 ) and N‐(4‐methylphenyl)acetamide ( L3 ) has been examined in Pd‐catalyzed Suzuki–Miyaura reaction of arylboronic acid with aryl bromides at room temperature. The complex 1L3 exhibited efficient activity in the Suzuki–Miyaura reaction (up to 99% isolated yield) under mild reaction conditions. Copyright © 2014 John Wiley & Sons, Ltd.     

Suzuki–Miyaura coupling reactions of aryl chlorides catalyzed by a new nickel(II) σ‐aryl complex

A new nickel(II) σ‐aryl complex, trans‐chloro(9‐phenanthrenyl)bis(triphenylphosphine)nickel(II), was used as a precatalyst for the Suzuki–Miyaura coupling reactions of aryl chlorides. The catalytic conditions were optimized by investigating the cross‐coupling of p‐chloroanisole with phenylboronic acid. The results show that this complex is efficient for both electron‐rich and electron‐deficient aryl chlorides, though it gives better yields for activated arylboronic acids than deactivated ones. All isolated cross‐coupled biaryl products have been characterized by ¹H and ¹³C NMR, and their spectral data are consistent with those reported. Side products from the coupling of arylboronic acid with the precatalyst complex have also been isolated and characterized, which is helpful for understanding the coupling mechanism. Copyright © 2013 John Wiley & Sons, Ltd.     

Rational Design of an Iron‐Based Catalyst for Suzuki–Miyaura Cross‐Couplings Involving Heteroaromatic Boronic Esters and Tertiary Alkyl Electrophiles

Suzuki–Miyaura cross‐coupling reactions between a variety of alkyl halides and unactivated aryl boronic esters using a rationally designed iron‐based catalyst supported by β‐diketiminate ligands are described. High catalyst activity resulted in a broad substrate scope that included tertiary alkyl halides and heteroaromatic boronic esters. Mechanistic experiments revealed that the iron‐based catalyst benefited from the propensity for β‐diketiminate ligands to support low‐coordinate and highly reducing iron amide intermediates, which are very efficient for effecting the transmetalation step required for the Suzuki–Miyaura cross‐coupling reaction.     

Polyaniline‐anchored palladium catalyst‐mediated Mizoroki–Heck and Suzuki–Miyaura reactions and one‐pot Wittig–Heck and Wittig–Suzuki reactions

A polyaniline‐anchored palladium catalyst was prepared and screened for coupling reactions of aryl halides. The robust and recyclable catalyst was effective in Mizoroki–Heck and Suzuki–Miyaura reactions of aryl bromides and aryl iodides. The catalyst system was further employed for one‐pot Wittig–Heck and Wittig–Suzuki combinations to build conjugated compounds in good conversions. Copyright © 2014 John Wiley & Sons, Ltd.     

Highly efficient orthopalladated complexes of second and third benzyl amine for catalyzing the Suzuki cross‐coupling reaction

In this work, ortho‐palladated complexes [Pd(µ‐Cl)(C₆H₄CH₂ NRR′‐κ²‐C,N)]₂ and [Pd(C₆H₄CH₂NH₂‐2‐C,N)Cl(Y)] were tested in the Suzuki–Miyaura cross‐coupling reaction. Cyclopalladated Pd(II) complexes as thermally stable catalysts can activate aryl bromides and chlorides. These complexes were active and efficient catalysts for the Suzuki–Miyaura reaction of aryl bromides and even less reactive aryl chlorides. The cross‐coupled products of a variety of aryl bromides and aryl chloride with phenylboronic acid in methanol as solvent at 60 °C were produced in excellent yields. Copyright © 2010 John Wiley & Sons, Ltd.     

Highly Efficient Palladacycle/Dihydroimidazolium Chloride System for the Suzuki‐Miyaura Cross‐Coupling of Aryl Halides (I,Br, Cl) with Arylboronic Acids

A combination of a tertiary amine‐based palladacycle and an N‐heterocyclic carbene ligand precursor ( 1 , N,N‐bis‐mesityl‐4,5‐dihydroimidazolium chloride) has been applied to catalyze the Suzuki‐Miyaura cross‐coupling of aryl halides with arylboronic acids. The substrate scope is general: a variety of electron rich and deficient aryl halides (I, Br, Cl) and arylboronic acids were found to undergo the cross‐coupling reaction in good to excellent yields at low catalyst loading of 0.01–1 mol%.