Benzimidazolin‐2‐ylidene–palladium‐catalysed coupling reactions of aryl halides

The in situ prepared three‐component system Pd(OAc)₂–1,3‐dialkylbenzimidazolium chlorides ( 2a – f ) and Cs₂CO₃ catalyses, quantitatively, the Suzuki cross‐coupling of deactivated aryl chlorides and Heck coupling reactions of aryl bromide and iodide substrates. The 1,3‐dialkylbenzimidazolium salts ( 2a – f ) were characterized by conventional spectroscopic methods and elemental analysis. Copyright © 2005 John Wiley & Sons, Ltd.     

Palladium-catalyzed cascade reactions of benzyl halides with N-allyl-N-(2-butenyl)-p-toluenesulfonamide

Reaction of benzyl halides with N-allyl-N-(2-butenyl)-p-toluenesulfonamide 1 in the presence of a palladium catalyst afforded dihydropyrroles 3 in moderate to excellent yields. It is proposed that the cyclic products were formed via a palladium-catalyzed cascade cyclization-coupling process.     

Synthesis of Arylethylene or Diarylethylene Compounds by Pd-Catalyzed Heck Coupling Reaction

We have developed an effective palladium-catalyzed arylation or diarylation couplings of olefins with various aryl halides in the presence of readily available ligands. This method is simple, economical, and practical for the synthesis of arylethylene and diarylethylene.

Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for full experimental and spectral details.     

Leaching from Heterogeneous Heck Catalysts: A Computational Approach

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＨｅｃｋｒｅａｃｔｉｏｎｉｓｔｈｅＣ—ＣｃｏｕｐｌｉｎｇｏｆａｎａｒｙｌｈａｌｉｄｅｗｉｔｈａｎａｌｋｅｎｅｖｉａａＰｄｂａｓｅｄｃａｔａｌｙｓｔ[1] ,ａｎｄｉｓａｔｒｅｍｅｎｄｏｕｓｌｙｖｅｒｓａｔｉｌｅｓｙｓｔｅｍａｃｃｏｍｍｏｄａｔｉｎｇｍａｎｙｄｉｆｆｅｒｅｎｔｓｕｂｓｔｒａｔｅｓａｓｗｅｌｌａｓｃａｔａｌｙｓｔｓ .Ａｃｏｍ ｐｒｅｈｅｎｓｉｖｅｒｅｖｉｅｗａｒｔｉｃｌｅｈａｓｒｅｃｅｎｔｌｙｂｅｅｎｐｕｂｌｉｓｈｅｄ ,ｗｈｉｃｈｎｉｃｅｌｙｉｌｌｕｓｔｒａｔ…     

Palladium nanoparticles immobilized on EDTA‐modified Fe3O4@SiO2 nanospheres as an efficient and magnetically separable catalyst for Suzuki and Sonogashira cross‐coupling reactions

In this study, a novel heterogeneous palladium catalyst was synthesized by anchoring palladium onto ethylenediaminetetraacetic acid (EDTA)‐coated Fe₃O₄@SiO₂ magnetic nanocomposite and used for the Suzuki and Sonogashira cross‐coupling reactions. The properties of the magnetic catalyst were characterized by FT‐IR, XRD, TEM, FE‐SEM, DLS EDX, XPS, N₂ adsorption‐desorption isotherm analysis, TGA, VSM, elemental analysis and the loading level of Pd in catalyst was measured to be 0.51 mmol/g by ICP. The catalyst was used in Suzuki cross‐coupling reactions of various aryl halides, including less reactive chlorobenzenes with phenylboronic acid without any additive or ligand under green conditions. Furthermore, we have reported this recyclable catalytic system for Sonogashira cross‐coupling reactions of various aryl halides (I, Br, Cl) under copper and ligand‐free conditions in the presence of DMF/H₂O (1:2/v:v) as a solvent. The magnetic catalyst could also be separated by an external magnet and reused six times without any significant loss of activity.     

Iminophosphine palladium(II) complexes: synthesis,characterization, and application in Heck cross‐coupling reaction of aryl bromides

Palladium(II) complexes containing phosphorus and nitrogen donor atoms (iminophosphine), dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐2‐trifluoromethylaniline}palladium(II) 1 , dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐3‐trifluoromethylaniline}palladium(II) 2 , dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐2‐methylaniline}palladium(II) 3 , dichlorido{N‐[2‐(diphenylphosphino)benzylidene]‐3‐methylaniline}palladium(II) 4 have been successfully synthesized and fully characterized by FT‐IR and NMR (¹H, ³¹P, ¹⁹F, and ¹³C) spectroscopy techniques. These complexes were first step tested in the reaction of bromobenzene and styrene to determine the optimal coupling reaction conditions and then successfully applied as catalysts for Heck cross‐coupling reactions of activated and deactivated aryl bromides with styrene derivatives and several acrylates. Copyright © 2014 John Wiley & Sons, Ltd.     

A new synthesis of flavonoids via Heck reaction

Several naturally occurring flavonoids have been synthesised following a new proposed method based on the use of the Heck reaction. The key step involves the coupling of an aryl vinyl ketone with an aryl iodide. This procedure affords the flavonoid moiety in a single step.     

Palladium‐catalyzed Heck coupling of 2‐vinylpyridine with aryl chlorides

An efficient PdCl₂(PCy₃)₂‐catalyzed cross‐coupling reaction of 2‐vinylpyridine with aryl chlorides to afford trans ‐2‐styrylpyridines with a variety of functional groups on the benzene ring is described. Copyright © 2008 John Wiley & Sons, Ltd.     

1,3-二烷基咪唑啉/Pd催化卤代芳烃的Heck和Suzuki反应

合成并表征了一种新型的有空间需求的N-杂环卡宾前驱体 1,3-二烷基咪唑啉盐. 这些咪唑啉盐与乙酸钯结合形成的高活性催化剂,可在温和条件下催化氯代和溴代芳烃的He ck和Suzuki交叉偶联反应.     

The Heck reaction of aryl bromides: a green protocol for synthesis of 2-ethylhexyl-4-methoxy cinnamate

Abstract

Deactivated aryl halide 4-bromoanisole and electron poor olefin 2-ethylhexyl acrylate were shown to undergo palladium catalyzed Heck reaction with the utilization of a cost-effective, thermally robust and unexplored morpholine-based ionic liquid. The developed protocol gives an environmentally friendly process for the synthesis of 2-ethylhexyl-4-methoxy cinnamate, an important UV-B sunscreen agent.     

A Convenient Procedure for the Synthesis of 4,6-Disubstituted 2-OXO-2H-Pyran-5-carboxylic Esters.

A simple procedure for the synthesis of 2H-pyran-2-ones 2a is described: The initial Michael addition product of β-ketoester anions with acetylenic esters readily cyclizes under the basic reaction conditions to give the α-pyrones 2a (Scheme 2).     

Convenient Procedure for Dethioketalisation in Nitrogen Heterocycles

Regeneration of Carbonyl compounds from the corresponding thioketals in nitrogen heterocycles have been effected using Dowex 50W acidic catalyst in reasonable yields.     

钯催化卤代芳烃的胺化反应研究

钯催化卤代芳烃胺化是形成Car-N的重要方法.配体的发展扩展了底物的适用范围, 提高了反应的选择性,实现了廉价易得的氯代芳烃的胺化,弱碱的使用提高了官能团的兼 容性,因此Pd催化芳胺化广泛应用于合成芳胺类化合物.本文以卤代芳烃为线索,对钯催化偶联胺化反应的研究进展进行了综述和展望.     

Palladium-catalyzed direct arylation of thiazoles with aryl bromides

Thiazole, 2-phenyl or -alkyl substituted one and benzothiazole are efficiently arylated with aryl bromides at the 2- and/or 5-position(s) in the presence of Pd(OAc)₂ and a bulky phosphine ligand using Cs₂CO₃ as base. 2-Phenyl-5-thiazolecarboxanilide undergoes successive diarylation at the 4- and 5-positions accompanied by decarbamoylation.     

A Convenient Palladium-Catalyzed Carbonylative Synthesis of (E)-3-Benzylidenechroman-4-ones

A convenient palladium-catalyzed carbonylation reaction for the efficient synthesis of (E)-3-benzylidenechroman-4-ones has been developed. Using TFBen as a solid CO source, a range of substituted (E)-3-benzylidenechroman-4-ones were prepared in moderate to good yields with 2-iodophenols and allyl chlorides as the substrates. Additionally, substituted quinolin-4(1H)-ones can also be obtained with 2-iodoaniline as the starting material.     

Ethanol‐promoted reductive homocoupling reactions of aryl halides catalyzed by palladium on carbon (Pd/C)

Homocoupling reactions of aryl bromides or iodides proceeded smoothly with palladium on carbon (Pd/C) catalyst, ethanol and base in dimethyl sulfoxide (DMSO) to afford exclusively symmetric biaryls in good to excellent yields. Ethanol was first used as a reducing agent in situ to reduce the Pd²⁺/C species into Pd⁰/C active species to complete the catalytic redox cycle. It was found that ethanol can promote the Pd/C‐catalyzed reductive homocoupling of aryl iodides and bromides efficiently in the presence of base. A reaction mechanism has been put forward and discussed. Copyright © 2010 John Wiley & Sons, Ltd.