Suzuki Coupling Reaction Catalyzed by Cyclopalladated Complexes of Tertiary Arylamines in Ionic Liquid

Suzuki cross-coupling reaction of phenylboronic acid with aryl halides catalyzed by cyclopalladated complexes of tertiary arylamines immobilized in ionic liquid [Bmim]^＋BF4^- was reported. The catalytic system proved to be efficient and be reused at least 3 times without significant loss of activity.     

Rapid Microwave‐Promoted Catalyst‐ and Solvent‐Free Suzuki‐Type Coupling Reaction

The catalyst‐ and solvent‐free Suzuki coupling reaction of sodium tetraphenylborate with hypervalent iodonium salts was achieved under microwave irradiation in the absence of a base. A convenient method for formation of carbon–carbon bonds afforded good yields in a short time.     

Inhibition of Homo-coupling of Arylboronic Acids in Ligand Free Pd（ll）-Catalyzed Suzuki Reaction

A series of solvents were examined for the ligand free Pd（II）-catalyzed Suzuki reaction of 4-bromotoluene with phenylboronic acid. It was found that the PdCl2/i-PrOH system could efficiently inhibit the homo-coupling of phenylboronic acid and give a cross-coupling product in high yields. The substrates with a wide variety of functional groups were tolerated in the system. A possible mechanism for this system was proposed.     

Rapid Microwave‐Promoted Base‐Free Suzuki Coupling Reaction of Sodium Tetraphenylborate with Hypervalent Iodonium Compounds in Water

The palladium chloride–catalyzed Suzuki coupling reaction of sodium tetraphenylborate with hypervalent iodonium salts and iodanes was achieved under microwave irradiation in water without base. A convenient and rapid method for formation of carbon–carbon bonds had excellent yields.     

Mannich‐Type Reaction Catalyzed by Silica‐Supported Fluoroboric Acid under Solvent‐Free Conditions

Three‐component Mannich‐type reaction of aldehydes, aromatic amines, and silyl enolate proceeded smoothly to afford β‐amino carbonyl compounds with good yields in the presence of a catalytic amount of HBF₄‐SiO₂.     

Total Synthesis of (−)-Batrachotoxin Enabled by a Pd/Ag-Promoted Suzuki–Miyaura Coupling Reaction

Batrachotoxin is an extremely potent cardio- and neurotoxic steroidal alkaloid found in certain species of frogs, birds, and beetles. The steroidal 6/6/6/5-membered carbocycle (ABCD-ring) is U-shaped and functionalized with two double bonds, a six-membered C3-hemiacetal across the AB-ring, a seven-membered oxazepane on the CD-ring, and a dimethylpyrrolecarboxy group at the D-ring carbon chain. These structural features present an unusual and formidable synthetic challenge. Herein we report a total synthesis of batrachotoxin based on a newly devised convergent strategy through a 22-step sequence. Enantiopure AB-ring and D-ring fragments were prepared and subjected to a crucial C(sp²)−C(sp²) coupling reaction. Although both C(sp²) centers were sterically encumbered by proximal tetrasubstituted carbon atoms, Ag₂O strongly promoted the Pd(PPh₃)₄-catalyzed Suzuki–Miyaura coupling reaction at room temperature, thereby connecting the two fragments without damaging their preexisting functionalities. Subsequent treatment with t-BuOK induced Dieckmann condensation to cyclize the C-ring. The judiciously optimized functionalizations realized oxazepane formation, carbon chain extension, and pyrrole carboxylic acid condensation to deliver batrachotoxin.     

Recyclable and Ligandless Suzuki Coupling Catalyzed by Carbon Nanotube‐Supported Palladium Nanoparticles Synthesized in Supercritical Fluid

Carbon nanotube–supported palladium nanoparticles prepared by a supercritical fluid deposition method show high activities for catalyzing Suzuki coupling reactions, and the catalysts can be recycled and reused at least six times without losing activity.     

Microwave-promoted Palladium Catalyzed Suzuki Cross-coupling Reaction in Water

Suzuki coupling is probably the most versatile approach among the cross-coupling reactions and the reaction has long been the subject of intensive work in the area of transition-metal chemistry1. In recent years, various modifications involving the catalyst, solvents, bases, reaction conditions and synthetic technique have been developed 2. The Suzuki cross-coupling reaction in water is more safe, economical. It is an environmentally friendly alternative in organic synthesis. The use of w…     

Microwave-promoted Palladium Catalyzed Suzuki Cross-coupling Reaction in WaterI

A simple, rapid and environmental friendly method for the synthesis of biaryl compounds under microwave irradiation is reported.     

Synthesis of Flurbiprofen via Suzuki Reaction Catalyzed by Palladium Charcoal in Water

Flurbiprofen 1, an excellent nonsteroidal antiinflammatory drug, was synthesized in 5 steps in 69% overall yield. The key step of constructing the biaryl fragment was successfully achieved via Pd/C-catalyzed Suzuki coupling reaction in water using sodium tetraphenylborate as phenylation reagent.     

Palladium Catalyzed Suzuki Cross-coupling Reaction in Molten Tetra-n-butylammonium Bromide

A practical procedure for palladium catalyzed Suzuki cross-coupling reaction of arylboronic acids with aryl halides, including aryl chlorides in molten tetra-n-butylammonium bromide (TBAB) was developed. The reaction exhibits high efficiency and functional group tolerance. The recovery of the catalyst and molten n-Bu4NBr was also investigated.     

Efficient Biginelli Reaction Catalyzed by Sulfamic Acid or Silica Sulfuric Acid under Solvent‐Free Conditions

Sulfamic acid efficiently catalyzes the three‐component condensation reaction of aldehydes, 1,3‐dicarbonyl compounds, and urea/thiourea under solvent‐free conditions to afford the corresponding dihydropyrimidinones and thio‐derivatives in high yields. Silica sulfuric acid is also found to be an efficient catalyst for the Biginelli reaction under solvent‐free conditions. Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of giving good yields and requiring short reaction times.     

Heck Reaction Catalyzed by Palladacycle in Neat Water

Cydopalladated ferrocenylimine has been found to be a type of excellent phosphine-free catalyst for Heck reactions in neat water with both higher yields and turnover numbers than those reported in the literature up to now. Some commercial emulsifying agents, indodin~ the commonly used quaternary ammonium salts, have been proved to be excellent additives in the catalysis of the reactions. Not only aromatic iodide, but also aromatic bromide could be coupled with the olef‘ms. All rcactions were able to be conducted in air under refluxlng condition.     

DFT Investigation on the Mechanism of Pd（0） Catalyzed Sonogashira Coupling Reaction

Based on DFT calculations, the catalytic mechanism of palladium(0) atom, commonly considered as the catalytic center for Sonogashira cross-coupling reactions, has been analyzed in this study. In the cross-coupling reaction of iodobenzene with phenylacetylene without co-catalysts and bases involved, mechanistically plausible catalytic cycles have been computationally identified. These catalytic cycles typically occur in three stages: 1) oxidative addition of an iodobenzene to the Pd(0) atom, 2) reaction of the product of oxidative addition with phenylacetylene to generate an intermediate with the Csp bound to palladium, and 3) reductive elimination to couple the phenyl group with the phenylethynyl group and to regenerate the Pd(0) atom. The calculations show that the first stage gives rise to a two-coordinate palladium (Ⅱ) intermediate (ArPdI). Starting from this intermediate, the second oxidative stage, in which the C–H bond of acetylene adds to Pd(Ⅱ) without co-catalyst involved, is called alkynylation instead of transmetalation and proceeds in two steps. Stage 3 of reductive elimination of diphenylacetylene is energetically favorable. The results demonstrate that stage 2 requires the highest activation energy in the whole catalysis cycle and is the most difficult to happen, where co-catalysts help to carry out Sonogashira coupling reaction smoothly.     

Solvent‐Free,Palladium‐Catalyzed Suzuki–Miyaura Cross‐Couplings of Aryl Chlorides with Arylboronic Acids

Pd(MeCN)₂Cl₂/PCy₃ was found to be an efficient catalytic system for the Suzuki–Miyaura cross‐couplings of aryl chlorides with arylboronic acids under solvent‐free conditions. Furthermore, the presence of the conventional solvents had deleterious effect on the reaction. In the presence of Pd(MeCN)₂Cl₂, PCy₃, and TBAF (tetra‐n‐butylammonium fluoride), a number of aryl chlorides including heteroaryl chlorides were coupled with arylboronic acids or heteroarylboronic acids smoothly to afford the corresponding products in moderate to excellent yields.     

Suzuki Coupling of Cyclopropylboronic Acid With Aryl Halides Catalyzed by a Palladium–Tetraphosphine Complex

The tetraphosphine all‐cis‐1,2,3,4‐tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) in combination with [Pd(C₃H₅)Cl]₂ affords a very efficient catalyst for the coupling of cyclopropylboronic acid with aryl bromides and aryl chlorides. Higher reactions rates were observed with aryl bromides than with aryl chlorides; however, even in the presence of 1–0.4% of catalyst, a few aryl chlorides gave the coupling products in good yields. A wide variety of substituents such as alkyl, methoxy, trifluoromethyl, acetyl, benzoyl, formyl, carboxylate, nitro, and nitrile on the aryl halides are tolerated. The coupling reaction of sterically very congested aryl bromides such as bromomesitylene or 2,4,6‐triisopropylbromobenzene also proceeds in good yields.     

Pinacol Coupling Reactions Catalyzed by Active Zinc

The facile carbon-carbon bond formation is a forever goal and indispensable tool in organic synthesis1. Metal-mediated coupling reactions as highly efficient processes are always a major focus of directed synthesis2. Pinacol coupling reactions have been recognized to be efficient and selected alternatives for preparing several kinds of compounds3, not to mention those can be as versatile tools for preparing building blocks or exerted on synthesizing natural products in several key steps4. The …     

Suzuki Coupling of 2‐Chloroacrylonitrile,Methyl 2‐Chloroacrylate,or 2‐Chloroprop‐1‐en‐3‐ol with Arylboronic Acids Catalyzed by a Palladium‐Tetraphosphine Complex

The tetraphosphine all‐cis‐1,2,3,4‐tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) in combination with [Pd(C₃H₅)Cl]₂ affords an efficient catalyst of the coupling of 2‐chloroacrylonitrile with arylboronic acids. In the presence of 1% catalyst, the 2‐arylacrylonitrile derivatives were obtained in medium to good yields. A variety of substituents such as alkyl, methoxy, fluoro, trifluoromethyl, formyl, or nitro on the arylboronic acid are tolerated. The cross‐coupling reactions of methyl 2‐chloroacrylate with arylboronic acids give simple access to 2‐phenylacrylate derivatives, which are useful precursors for the synthesis of biologically active compounds such as ibuprofen, ketoprofen, and naproxen.     

Efficient DMF‐Catalyzed Coupling of Epoxides with CO2 under Solvent‐Free Conditions to Afford Cyclic Carbonates

To develop a simple, low‐molecule, and cost‐effective organocatalyst for the coupling of epoxides with CO₂, we have screened this coupling reaction in different organic solvents and found that DMF is an efficient organic catalyst for the coupling of epoxides with CO₂ to give cyclic carbonates in high yield. In some cases, the catalytic activity of DMF can be significantly increased by the addition of catalytic amount of H₂O.     

One‐Pot Preparation of Unsymmetrical Biaryls via Suzuki Cross‐Coupling Reaction of Aryl Halide using Phase‐Transfer Catalyst in a Biphasic Solvent System

A one‐pot synthetic method of unsymmetrical biaryls was developed via the Suzuki cross‐coupling reaction of aryl halide using a phase‐transfer catalyst in a biphasic solvent system.