Palladium-catalyzed Suzuki cross-coupling reactions in a microemulsion

An enhancement of palladium-catalyzed Suzuki cross-coupling reactions between substrates possessing long-chain alkyl or oxyalkyl substituents in two-phase media, in the presence of sodium dodecylsulfate, is shown. Quantitative evaluations of the influence of SDS on the reaction rates were determined.     

Palladium supported on hydrotalcite as a catalyst for the Suzuki cross-coupling reaction

The efficiency of various palladium salts as catalysts in the Suzuki cross-coupling reaction, and the influence of the base and temperature used on its conversion, were studied. The use of PdCl₂ supported on hydrotalcite as catalyst in the presence of potassium carbonate as base was found to provide the best results. Reaction temperatures above 90 °C ensured conversion levels on a par with those for many homogeneous catalysts.     

Chitosan-supported palladium(0) catalyst for microwave-prompted Suzuki cross-coupling reaction in water

A chitosan-supported palladium (Pd) (0) catalyst was prepared by simple adsorption of palladium(II) ion onto chitosan beads and a subsequent reduction process. To maintain mechanical stability, the chitosan-supported palladium(0) catalyst was cross-linked with either glutaraldehyde or diglycidyl ether polyethylene glycol. The catalysts were utilized for the Suzuki cross-coupling reaction in water. The catalyst, in the presence of a tetrabutylammonium bromide (TBAB) additive, showed excellent catalytic activity in microwave-prompted Suzuki cross-coupling reactions using various aryl halides and boronic acids. In addition, the catalyst was successfully reused up to five times without significant loss of catalytic activity.     

Nation-Teflon bimembrane-supported palladium catalysts for Suzuki coupling reactions

Nation-Teflon bimembrane was used as an efficient support for the preparation and application of heterogeneous palladium catalysts.The supported palladium catalysts exhibit high activity and stability in the Suzuki cross-coupling of aryl bromides with arylboronic acids to afford the corresponding biaryls in good to excellent yields,and can be readily recovered and reused several times without significant loss of activity.     

Synthesis of arylated chalcone derivatives via palladium cross-coupling reactions

A useful protocol for arylation of the olefin double bond of chalcones to afford tri- and tetra-substituted chalcone derivatives is reported. The protocol begins with the Heck reaction between chalcones and aryl iodides providing β-arylchalcones. This reaction tolerates various functional groups on both rings, as well as deactivated aryl iodides. The products are obtained in moderate to excellent yields and the (E)-β-arylchalcones (E:Z?>?96:4) can be isolated via precipitation. Competitive Heck reactions pointed to a significant effect of ring one substituents on the reaction rate, while substituents on ring two have a much smaller effect. To access α,β-diarylchalcones, a sequential bromination-Suzuki cross coupling strategy was applied to the β-arylated compounds which afforded double arylated chalcone derivatives in 60–99% yield over two steps.     

Amphiphilic polymer supported N-heterocyclic carbene palladium complex for Suzuki cross-coupling reaction in water

We synthesized amphiphilic polymer-supported N-heterocyclic carbene (NHC) precursor resins by loading polyethylene glycol (PEG) containing imidazolium groups on Merrifield resin. These PS-PEG-NHC precursor resins were compatible with water and readily formed a stable complex with palladium. These PS-PEG-NHC-Pd catalysts showed excellent catalytic activity for Suzuki cross-coupling reactions of various aryl iodides and bromides with phenylboronic acid in water than the previously described polystyrene based catalysts. In addition, the PS-PEG-NHC-Pd catalysts continued to provide excellent catalytic activity in Suzuki cross-coupling reactions after five consecutive recycles.     

Pd-CNT-catalyzed ligandless and additive-free heterogeneous Suzuki-Miyaura cross-coupling of arylbromides

Pd-CNT efficiently catalyzed Suzuki-Miyaura coupling of arylbromides under ligandless and additive-free conditions in aqueous media. For hydrophilic substrates, the reaction could be carried out in neat water.     

Impregnated palladium on magnetite, a new catalyst for the ligand-free cross-coupling Suzuki-Miyaura reaction

A new catalyst for the cross-coupling Suzuki-Miyaura reaction is reported. The impregnated palladium on magnetite catalyst is very easy to prepare using the standard impregnation methodology. This catalyst avoids the use of any type of expensive and difficult handle organic ligand, showing excellent yields, under mild reaction conditions, for the classical formation of biaryl compounds. The catalyst is very easy to remove from the reaction medium, only by using a simple magnet, and it could be re-used up to three times with only a slightly decrease of the chemical yield.     

An efficient and simple protocol for a PdCl2-ligandless and additive-free Suzuki coupling reaction of aryl bromides

A highly efficient, convenient, and environmentally friendly protocol was developed for the PdCl₂-catalyzed ligandless and additive-free Suzuki reaction of aryl bromides with arylboronic acids in water/ethanol.     

Iminophosphine palladium catalysts for Suzuki carbonylative coupling reaction

Three iminophosphine ligands having soft phosphorus and hard nitrogen atoms and their Pd(II) complexes were synthesized and characterized using ¹H NMR, ¹³C NMR, ³¹P NMR and Fourier transform infrared spectroscopic techniques. Also, electrochemical properties of the iminophosphines and their Pd(II) complexes were investigated in acetonitrile–tetrabutylammonium perchlorate solution with cyclic and square wave voltammetry techniques. All Pd(II) complexes were evaluated as catalysts for carbonylative cross‐coupling reactions of aryl iodides with phenylboronic acid. The Suzuki carbonylation of aryl iodides at 80 °C under balloon pressure of carbon monoxide in the presence of K₂CO₃ as a base was examined, and good to high conversions and excellent selectivities were obtained.     

Activity of palladium on charcoal catalysts in cross-coupling reactions

Comparison of the activity of several commercially available Pd/C catalysts in C-C, C-N, and C-S bond forming cross-coupling reactions has demonstrated the importance of the choice of the catalyst source. Investigations showed marked difference in activity between the catalysts. Moreover, the catalytic activity of each catalyst varies with respect to the coupling. The first Pd/C catalyzed Hiyama coupling is reported.     

A Convenient and General Method for Pd-Catalyzed Suzuki Cross-Couplings of Aryl Chlorides and Arylboronic Acids

From only commercially available reagents a wide array of Suzuki cross-couplings of aryl chlorides with arylboronic acids can be effected in excellent yield [Eq. (a)]. This development provides a general solution to a long-standing limitation of this extremely powerful process—the poor reactivity of inexpensive and readily accessible aryl chlorides. dba=dibenzylideneacetone.     

Synthesis of chiral binaphthalenes using the asymmetric Suzuki reaction

The synthesis of atropisomeric 1,1′-binaphthalenes can be achieved using an asymmetric Suzuki cross-coupling reaction. The Suzuki reaction leading to such hindered compounds is challenging and competing hydrolytic deboronation frequently dominates unless carefully chosen conditions are employed. The simple, standard mechanism is inadequate when describing the Suzuki coupling of hindered partners. Evidence suggests that the key step leading to asymmetry is transmetallation (delivery of the organometallic by the asymmetric ligand) and the reactions operate under kinetic control. Reductive elimination (itself likely to be triggered by oxidative addition of another molecule of halide) is fast compared with equilibration (epimerisation and/or cis-trans isomerisation).     

Stereoselective synthesis of 1,3-dienylstannanes by palladium catalyzed cross-coupling reactions

(Z)-α-Bromovinylstannanes are new difunctional group reagents, which undergo palladium catalyzed cross-coupling reactions with (E)-alkenylzirconium complexes to give stereoselectively 1,3-dienylstannanes in good yields.     

A novel fluorous palladium catalyst for Suzuki reaction in fluorous media

Palladium(II) perfluorooctanesulfonate [Pd(OSO₂R_f8)₂] catalyses the highly efficient Suzuki reaction in the presence of a catalytic amount of perfluoroalkylated-pyridine as a ligand in a fluorous biphase system (FBS). The fluorous phase containing the active palladium species is easily separated and can be reused several times without a significant loss of catalytic activity.     

Palladium-catalyzed direct cross-coupling reaction between indenes and electron-deficient alkenes

An efficient methodology for oxidative cross-coupling of indene and derivatives with electron-deficient olefins catalyzed by palladium was developed. The corresponding diene products were obtained in moderate to good yields.     

Suzuki reaction of bromoallenes with arylboronic acids using an air-stable palladium complex Pd(Ph_2PCH_2CO_2)_2 as a precatalyst

<正>Suzuki reaction of bromoallenes with arylboronic acids was successfully performed by using an air-stable hemilabile P-O coordinated cyclopalladated complex Pd(Ph_2PCH_2CO_2)_2 as a precatalyst,and the corresponding coupling products were obtained in satisfactory to excellent yields.All products are unknown compounds which were characterized by ~1H NMR,~(13)C NMR,IR,and HRMS.     

光催化Suzuki偶联反应的非均相催化剂研究进展

Suzuki偶联反应作为构建C-C键的最有效的手段之一,在医药、染料和电子工业等领域扮演着重要的角色。传统的Suzuki偶联反应催化体系需要依赖化石能源产生的热能来驱动,不仅造成了不可再生资源的消耗,还会导致相应的环境问题。近年来,光催化技术和绿色有机合成化学蓬勃发展,利用可再生的太阳能光催化Suzuki偶联反应不但可以解决在催化反应过程中的能源与环境问题,还可以在温和条件下获得高产率的联苯化合物产物,正在受到人们的广泛关注。与均相光催化剂相比,非均相光催化剂具有良好的化学稳定性、便捷的可回收性与优异的循环利用性能等优点,因此成为光催化Suzuki偶联反应的研究重点。本文总结了非均相催化剂光催化Suzuki偶联反应的基本原理,介绍了近年来科研工作者对光催化Suzuki偶联反应中非均相催化剂的制备方法、催化性能以及可循环利用性等方面做的一系列研究。     

Simultaneous reduction of nitro- to amino-group in the palladium-catalyzed Suzuki cross-coupling reaction

An efficient method for palladium-catalyzed Suzuki cross-coupling reaction with simultaneous reduction of nitro- to amino-group has been developed. This method allows nitro-substituted aryl halides to readily react with arylboronic acids, to afford aryl substituted aniline in low to excellent yields. The reaction was catalyzed by Pd(OAc)₂ (3 mol %) at 150 °C under atmospheric pressure in the presence of K₂CO₃ (3 equiv) in DMF/H₂O (5/1).