Miyaura Reactions In Aqueous Media Research Articles

Amidophosphine‐stabilized palladium complexes catalyse Suzuki–Miyaura cross‐couplings in aqueous media

We report a simple and efficient procedure for Suzuki–Miyaura reactions in aqueous media catalysed by amidophosphine‐stabilized palladium complexes trans‐{L3PPh2}2PdCl2 (3), trans‐{L3PPhtBu}2PdCl2 (4), [Pd(η3‐C3H5)(L3PPh2)Cl] (5) and {Pd[2‐(Me2NCH2)C6H4](L3PPh2)Cl} (6). The acidity of the NH proton in complexes 3, 4, 5, 6 plays an important role in their catalytic activity. In addition, the palladium complexes cis‐{L1PPh2}PdCl2 (1) and trans‐{L2PPh2}2PdCl2 (2) stabilized by phosphines containing Y,C,Y‐chelating ligands L1,2 have also been found to be useful catalysts for Suzuki–Miyaura reactions in aqueous media. The method can be effectively applied to both activated and deactivated aryl bromides yielding high or moderate conversions. The catalytic activity of couplings performed in pure water increases when utilizing a Pd complex with more acidic NH protons. A decrease of palladium concentration from 1.0 to 0.5 mol% does not lead to a substantial loss of conversion. In addition, Pd complex 1 can be efficiently recovered using two‐phase system extraction. Copyright © 2016 John Wiley & Sons, Ltd.

High-turnover aminopyridine-based Pd-catalysts for Suzuki–Miyaura reaction in aqueous media

A high-turnover catalytic system based on commercially available aminopyridines (L) and PdCl2 has been developed for Suzuki–Miyaura reaction in aqueous media. Reactions of arylboronic acids with a wide range of aryl iodides, bromides and chlorides proceeded in the presence of these catalysts for a short time in aqueous media to afford the cross-coupling products in high yields. Furthermore, this protocol allows tolerating a wide range of functional groups.

Magnetically recoverable catalysts based on mono- or bis-(NHC) complexes of palladium for the Suzuki–Miyaura reaction in aqueous media: two NHC–Pd linkages are better than one

Pre-synthesized mono- and bis(NHC) palladium complexes have been grafted onto magnetic core/shell γ-Fe2O3/silica particles and tested as catalysts in model Suzuki-Miyaura coupling reactions. The bis(NHC) immobilized complex was found to be a robust catalyst that can operate under mild conditions in aqueous media, even for the activation of chloroarene, whereas the mono(NHC) counterpart rapidly deactivates. Moreover, it can be readily recovered by magnetic separation and reused many times, providing very high productivities, and with so low leaching of palladium that the crude products obtained contain ≤10 ppm Pd.

An imidazolium ionic compound-supported palladium complex as an efficient catalyst for Suzuki–Miyaura reactions in aqueous media

A water soluble and efficient ionic compound-supported palladium complex was prepared.

ChemInform Abstract: Amine‐Bridged Bis(phenol) Ligands for Efficient Pd‐Catalyzed Aqueous C—C Coupling Reactions.

AbstractA highly efficient protocol for the Pd‐catalyzed homocoupling of arylboronic acids (I) as well as Suzuki—Miyaura reactions in aqueous media is developed.

Palladium(II) complex with a potential N4-type Schiff-base ligand as highly efficient catalyst for Suzuki–Miyaura reactions in aqueous media

Two new air-stable palladium(II) complexes containing a N4-Schiff-base ligand have been synthesized and investigated as catalysts for the Suzuki–Miyaura reactions. The binuclear complex 2 has proven to be an excellent catalyst for additive-free Suzuki–Miyaura reactions of aryl bromides in neat water at room temperature and aryl chlorides in aqueous-glycerol at 80°C. Satisfactory to excellent yields of biaryls are obtained with a wide range of substrates with relatively low loading of catalyst.

Agarose hydrogel as an effective bioorganic ligand and support for the stabilization of palladium nanoparticles. Application as a recyclable catalyst for Suzuki–Miyaura reaction in aqueous media

In this article, the usefulness of an agarose hydrogel as an effective bioorganic ligand and support for the entrapment and stabilization of palladium nanoparticles is described. We have applied this catalyst under low loading of the supported palladium nanoparticles for the Suzuki–Miyaura coupling reaction of different aryl iodides, bromides and chlorides with phenylboronic acid in the absence of phosphorous ligands or any organic co-solvents or phase transfer additives. The catalyst was efficiently recycled for six runs, retaining its activity within the limit of the experimental error. ICP analysis of the catalyst shows Pd content of the agarose hydrogel is a low amount. The analysis of the reaction mixture by the ICP technique also showed the leaching of the catalyst was negligible. The work-up of the mixture can also be handled under highly green conditions in water. However, this catalytic system can be easily applied for scaled-up protocols.

ChemInform Abstract: Kaiser Oxime Resin Derived Palladacycle: A Recoverable Polymeric Precatalyst in Suzuki—Miyaura Reactions in Aqueous Media.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Kaiser oxime resin-derived palladacycle: A recoverable polymeric precatalyst in Suzuki–Miyaura reactions in aqueous media

Abstract Representative cross-coupling reactions of aryl bromides with different types of aryl-, alkyl, trivinylboroxine–pyridine complex, and alkenylboronic acids are performed using a polymer-bonded palladacycle derived from Kaiser oxime resin as precatalyst and potassium carbonate as base under water reflux. These processes afford biphenyls, alkylbenzenes, styrenes, and stilbenes, respectively. The same boronic acids can be cross-coupled with representative allyl and benzyl chlorides using KOH as base in aqueous acetone at 50 °C providing allylbenzenes, diarylmethanes, and 1,4-pentadienes. The palladated polymer can be recovered by filtration and reused during 3–9 cycles with up to 5% of Pd leaching in each run. Very low Pd leaching levels in the crude product can be determined by ICP–OES analyses. The reaction does not work when Hg(0) is added. TEM analyses from the solution indicate the formation of Pd nanoparticles.

ChemInform Abstract: Supported Phosphine‐Free Palladium Catalysts for the Suzuki—Miyaura Reaction in Aqueous Media.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Supported phosphine-free palladium catalysts for the Suzuki–Miyaura reaction in aqueous media

The Suzuki–Miyaura reaction has been performed using a non-symmetrical salen-type palladium(II) catalyst that is readily immobilized onto Merrifield resin and functionalized silica. The catalysts combine high activity with the recoverability and reusability offered by a heterogeneous system, without the need for phosphine ligands or additives. The high content of water used in the reaction, which is more than 96% by volume, represents a green process that should have advantages for industrial applications. Leaching of the metal into solution from the supported catalyst proved to be negligible.

ChemInform Abstract: The First Use of Porphyrins as Catalysts in Cross‐Coupling Reactions: A Water‐Soluble Palladium Complex with a Porphyrin Ligand as an Efficient Catalyst Presursor for the Suzuki—Miyaura Reaction in Aqueous Media under Aerobic Conditions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The first use of porphyrins as catalysts in cross-coupling reactions: a water-soluble palladium complex with a porphyrin ligand as an efficient catalyst precursor for the Suzuki–Miyaura reaction in aqueous media under aerobic conditions

For the first time, a palladium complex with a porphyrin ligand is used as a catalyst precursor for cross-coupling reactions. The synthesis of a palladium complex with a phosphine-free and water-soluble potassium carboxylate salt of a porphyrin, and its evaluation in the Suzuki–Miyaura reaction of phenylboronic acid with aryl bromides (from electron-rich to electron-poor), in neat water, under aerobic conditions is described. Catalysis is performed at 100 °C for 4 h, using K 2CO 3 as base, and a substrate to catalyst molar ratio of 1000:1, leading to yields of coupling products in the range of 80–100%. The catalyst can be recycled and reused, but unfortunately, with a loss in activity.