双子季铵盐稳定的纳米钯催化Suzuki反应的研究

双子座季铵盐能够稳定现场产生的纳米钯粒子,该纳米钯粒子能有效地催化一系列芳基硼酸和芳基卤代烃发生Suzuki偶联反应.双子座季铵盐稳定的纳米钯粒子能够在空气中稳定存在,透射电镜(TEM)分析纳米钯粒子呈圆球形,粒径分布在5～25 nm.该方法具有反应条件温和、反应时间短、后处理简单方便等优点.     

Aqueous-phase, palladium-catalyzed cross-coupling of aryl bromides under mild conditions, using water-soluble, sterically demanding alkylphosphines

Sterically demanding, water-soluble alkylphosphines have been used in combination with various palladium salts in Suzuki, Sonogashira, and Heck couplings of aryl bromides under mild conditions in aqueous solvents. The tert-butyl-substituted ligands 2-(di-tert-butylphosphino)ethyltrimethylammonium chloride (t-Bu-Amphos) and 4-(di-tert-butylphosphino)-N,N-dimethylpiperidinium chloride (t-Bu-Pip-phos) in combination with palladium(II) salts were found to give catalysts that were significantly more active than catalysts derived from tri(3-sulfonatophenyl)phosphine trisodium (TPPTS). Suzuki couplings of unactivated aryl bromides occurred efficiently at room temperature in water/acetonitrile and water/toluene biphasic mixtures or in neat water. Notably, Suzuki couplings of hydrophilic aryl bromides gave high yields without using organic solvents for the reaction or purification. This methodology has been applied to a highly efficient synthesis of diflunisal. The catalyst derived from t-Bu-Amphos was recycled three times in Suzuki couplings in water/toluene before catalyst activity began to significantly drop. The average yield of four cycles was >80% per cycle. Heck and Sonogashira couplings were carried out under mild conditions (50 and 80 degrees C, respectively) with unactivated aryl bromides to give coupled products in high yield.     

Palladium complex containing two sterically hindered ligands as highly efficient catalyst for Suzuki–Miyaura reaction

A new palladium(II) complex containing two sterically hindered ligands, a P,P‐bonded diphosphine and N,N‐bonded Schiff base, within the same coordination sphere has been synthesized and investigated as a catalyst for the Suzuki–Miyaura cross‐coupling reactions of aryl halides with arylboronic acids. The reaction was highly efficient with aryl bromides in water at room temperature and aryl chlorides in dimethylformamide under relatively mild conditions. Excellent yields of coupling products were obtained for a wide range of aryl halides including heteroaryl halides with a low loading of catalyst. Copyright © 2015 John Wiley & Sons, Ltd.     

N‐Heterocyclic carbene/phosphite synergistically assisted Pd/C‐catalyzed Suzuki coupling of aryl chlorides

An N‐heterocyclic carbene and phosphite synergistically enhanced Pd/C catalyst system has been developed for Suzuki coupling of aryl chlorides and aryl boronic acids from commercially available Pd/C with sterically demanding N,N′‐bis(2,6‐diisopropylphenyl)imidazolylidene and trimethylphosphite. A remarkable increase in catalytic activity of Pd/C was observed when used along with 1 equiv. N,N′‐bis(2,6‐diisopropylphenyl)imidazolium chloride and 2 equiv. phosphite with respect to palladium in appropriate solvents that were found to play a crucial role in Pd/C‐NHC‐P(OR)₃‐catalyzed Suzuki coupling. A dramatic ortho‐substitution effect of carbonyl and nitrile groups in aryl chlorides was observed and explained by a modified quasi‐heterogeneous catalysis mechanism. The Pd/C catalyst could be easily recovered from reaction mixtures by simple filtration and only low palladium contamination was detected in the biparyl products. A practical process for the synthesis of 4‐biphenylcarbonitrile has therefore been developed using the N‐heterocyclic carbene/phosphite‐assisted Pd/C‐catalyzed Suzuki coupling. Copyright © 2013 John Wiley & Sons, Ltd.     

Palladium catalyzed ligand-free Suzuki cross-coupling reactions of benzylic halides with aryl boronic acids under mild conditions

A highly efficient Suzuki cross-coupling reaction between benzylic halides and aryl boronic acids using palladium chloride as catalyst in acetone:water (3:1) as the solvent system has been developed. High yields of products, mild reaction conditions and short reaction times in the absence of ligand are important features of this method.     

果胶负载钯催化剂的制备及Suzuki反应催化性能

以柑橘皮果胶为载体,采用吸附法制备了果胶负载钯催化剂,并将其应用于四苯硼钠与溴代芳烃的交叉偶联反应中.该反应体系以聚乙二醇400(PEG 400)/H2O为反应溶剂,三乙胺为碱,在空气中于110℃反应15~60 min,四苯硼钠中4个苯基均可顺利参与反应,高产率地获得相应的目标化合物.该方法具有条件温和、反应时间短、收率高且催化剂可循环利用等优点.     

Suzuki–Miyaura coupling catalyzed by palladium nanoparticles biosynthesized using Glycyrrhiza glabra as reducing and stabilyzing agent

An unprecedented environmentally friendly method has been developed for the synthesis of palladium nanoparticles supported on Glycyrrhiza glabra. The synthesized nanoparticles were utilized in Suzuki–Miyaura reaction between different aryl halides and aryl bronic acid in aqueous media. This heterogeneous catalyst can be reused and recycled repeatedly more than five times with only slight loss of its initial catalytic efficiency. This reaction carrid out under atmospheric pressure with high efficiency, unique and simple work‐up procedure and excellent yields.     

Sulfonated palladium(II) N‐heterocyclic carbene complex immobilized on nano–micro size poly(4‐vinylpyridinium chloride) for Suzuki‐Miyaura cross‐coupling reaction

The sulfonated palladium(II) N‐heterocyclic carbene complex Pd^II(NHC)SO₃^?, supported on poly(4‐vinylpyridinium chloride), was used as a heterogeneous, recyclable and active catalyst for the Suzuki–Miyaura reaction. This catalyst was applied for coupling of various aryl halides with phenylboronic acid and the corresponding products were obtained in excellent yields and short reaction times. The catalyst was characterized using Fourier transform infrared and diffuse reflectance UV–visible spectroscopies, scanning electron microscopy and elemental analysis. After each reaction, the catalyst was recovered easily by simple filtration and reused several times without significant loss of its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

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.     

Synthesis of diarylmethane derivatives from Pd-catalyzed cross-coupling reactions of benzylic halides with arylboronic acids

A simple catalyst precursor prepared in situ from palladium acetate and triphenylphosphine shows high activity for the Suzuki cross-coupling reaction of benzylic bromides and chlorides with aryl boronic acids. The reaction can be carried out at low catalyst loading (0.002-1 mol%) and under mild conditions (room temperature to 80 °C) furnishing diarylmethane derivatives in high yields (86-99%).     

Suzuki reaction with aryl bromides at room temperature in the presence of a simple “ligand-free” catalytic system

Possibility was examined of using the simplest catalytic system (palladium salt and NaOH) in ethanol or in a mixture of ethanol and water as a catalyst precursor in order to obtain high product yields in the Suzuki reaction with nonactivated aryl bromides at room temperature without an inert atmosphere or ligand additives.     

Macroporous polystyrene-supported palladium catalyst containing a bulky N-heterocyclic carbene ligand for Suzuki reaction of aryl chlorides

Macroporous polystyrene (MPS)-supported 1-mesitylimidazolium chloride resin was prepared by reacting macroporous chloromethyl polystyrene with 1-mesitylimidazole as a supported N-heterocyclic carbene (NHC) precursor for the immobilization of a palladium catalyst. This MPS-supported NHC precursor readily formed a stable complex with Pd(OAc)2, which effectively catalyzed the Suzuki reaction of aryl iodide and bromides at room temperature and even aryl chlorides at elevated temperatures (100 degrees C). This catalyst showed reusability in the Suzuki reaction of aryl bromide.     

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.     

Phosphine-free polystyrene-supported palladium(II) complex as an efficient catalyst for the Heck and Suzuki coupling reactions in water

A palladium complex, 1-phenyl-1,2-propanedione-2-oxime thiosemi-carbazone-functionalized polystyrene resin supported Pd(II), is found to be a highly active catalyst for the Heck reaction of methyl acrylate with aryl halides and Suzuki reaction of phenylboronic acid with aryl iodides and bromides, giving excellent yields. The reactions were performed under phosphine-free conditions in an air atmosphere. The palladium catalyst is easily separated, and can be reused for several times without a significant loss in its catalytic activity.     

Efficient synthesis of racemic and chiral alkenyl sulfoxides by palladium-catalyzed Suzuki coupling

Alkenyl sulfoxide derivatives are obtained in high yields through a palladium-catalyzed Suzuki/Miyaura cross-coupling reaction of racemic and chiral 1-halo sulfoxides with aryl and alkenyl boronic acids. Chiral substrates react with no loss of optical purity and high optical yields. The reaction takes place with different palladium catalysts, such as Pd(PPh₃)₄ or Pd(OAc)₂/DABCO. Although nitrogen ligands like DABCO lead to an active palladium catalyst, they are less effective than the phosphine ones.     

氯化钯多相催化无配体室温Suzuki-Miyaura反应

本文报道了温和及有效的氯化钯多相催化无配体Suzuki-Miyaura反应,反应在室温、敞口容器和短时间内完成。各种碘代芳烃、溴代芳烃和活泼的氯代芳烃与四苯硼钠和芳香有机硼酸偶联高产率生成相应的产物,而且催化剂可循环使用4次不降低活性。     

Green synthesis of fluorinated biaryl derivatives via thermoregulated ligand/palladium-catalyzed Suzuki reaction

Fluorinated compounds have attracted considerable attention in pharmaceuticals, agrochemicals and material science due to their unique physical properties. This paper reports an efficient and environmentally benign protocol for the Suzuki reaction of aryl halides with fluorinated arylboronic acids over a thermoregulated ligand/palladium catalyst using water as sole medium, affording a variety of fluorinated biaryls, including fluorinated liquid crystals, in excellent yields. The catalyst could be recycled four times with high activity. The active catalyst was proved to be a palladium/ligand complex via a mercury-poisoning test.     

Recyclable and highly active cationic 2,2′-bipyridyl palladium(II) catalyst for Suzuki cross-coupling reaction in water

A water-soluble and air-stable palladium(II)/cationic 2,2′-bipyridyl catalyst is proven to be a recyclable and extremely active catalyst for Suzuki reaction in aqueous and aerobic conditions. The conveniently prepared catalyst showed little loss in the catalytic process of the coupling between 4-bromoacetophenone and phenylboronic acid after five cycles. For the reactions of aryl chlorides, biaryls were formed in high yields under refluxing temperature in the presence of TBAB.     

Environmentally friendly synthesis of biaryls: Suzuki reaction of aryl bromides in water at low catalyst loadings

Pd(DPPF)Cl₂ is shown to be an extremely active catalyst for the Suzuki reaction of aryl bromides in water. This green procedure provides biaryls in excellent yields and high turnover numbers (TONs) (TONs up to 870,000 for the reaction of 1-bromo-4-nitrobenzene and phenylboronic acid). A small amount of PEG-2000 also allows the recycling of the palladium catalyst for three times without any significant loss of catalytic activity.     

Nickel-promoted ligand-free palladium-catalyzed Suzuki coupling reaction

Summary A Ni-promoted ligand free palladium catalyst system for Suzuki coupling of aryl bromides has been developed in high efficiency under mild reaction conditions. It was obtained in situ by introducing NiCl₂ to PdCl₂/PVP using a parallel high-throughput screening technique. A wide range of aryl bromides bearing a variety of functional groups was evaluated.