Copper‐Free,Efficient, Palladium (II)‐Catalyzed Coupling of Unactivated Aryl Iodides with Terminal Alkynes

Palladium(II)‐catalyzed coupling of terminal alkynes with unactivated aryl iodides occurs at room temperature in good to excellent yields in the presence of tetrabutylammounium bromide as additive and piperidine as base in a tetrahydrofuran–water solution without addition of any cuprous salts.     

Copper(Ⅱ) and 2,2′-Biimidazolyl-promoted Ullmann Coupling Reaction of Phenols and Aryl Iodides

Ullmann-type diaryl ether synthesis can be performed at 100℃ in good to excellent yields by aryl iodides asthe substrates under the assistance of copper(Ⅱ)and 2,2'-biimidazolyl.     

Convenient Synthesis of Aryl Ferrocenyl Ketone via Palladium‐Catalyzed Carbonylation Coupling

A series of aryl ferrocenyl ketones were prepared from iodoferrocene, phenylboronic acids, and CO via palladium‐catalyzed carbonylation coupling in a short time. The procedure was efficient and convenient and avoided formation of diacylated derivatives compared with currently available Friedel–Crafts acylation methodologies.     

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…     

Cross—Coupling of Aryl Iodides with Malononitrile Catalyzed by Palladium N—Heterocyclic Carbene Complex System

Eight N-heterocyclic carbenes (NHC),generated in situ from their imidazolium salts,as ligands of palladium complexes were used for the catalytic coupling of iodobenzene with malononi-trile anion,It was found that 1,3-bis(2,4,6-trimethylphenyl)-imidazolium chloride (IMesHCl)-Pd2(dba)3 catalytic system has the highest activity to obtain phenyl malononitrile among the imidazolium salts.The substituted iodoarenes reacted with malononitrile anions by using the catalytic system to give cross-coupling products in yields from 50% to 96%.     

Ligand‐Free Suzuki Coupling Reaction Catalyzed by Pd/C in Microemulsion

Ligand‐free Suzuki reactions catalyzed by Pd/C can be efficiently performed in TX100 microemulsions. A number of aryl halides, including aryl iodides, bromides, and chlorides, were coupled with arylboronic acids smoothly and efficiently to produce good to excellent yields.     

Copper‐Catalyzed Coupling Reaction of 2‐Thioxo‐4‐quinazolinone and Thieno[3,2‐d]pyrimidin‐4‐one Methane Sulphonamide with Aryl Iodides: Preparation of Potential COX‐2 Selective Inhibitors

Thio‐aryl methane sulfonamide derivatives of 4‐quinazolinone and thieno[2,3‐d]pyrimidin‐4‐one were synthesized using powdery copper/copper(I) iodide as catalyst; their structural elucidation is also reported. These derivatives were planned as sulfur bioisosteres of selective COX‐2 inhibitor drugs.     

Carbon Dioxide Promoted Palladium‐Catalyzed Cyclotrimerization of Alkynes in Water

Abstract

In water, CO₂ was found to promote the palladium‐catalyzed cyclotrimerization of alkynes. In the presence of PdCl₂, CuCl₂, and CO₂, both aryl and alkylalkynes afforded the corresponding cyclotrimerization products regioselectively in high yields. However, tert‐butylacetylene bearing a bulk group gave a dimerization product.     

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.     

A Dual Palladium and Copper Hydride Catalyzed Approach for Alkyl–Aryl Cross-Coupling of Aryl Halides and Olefins

We report an efficient means of sp²–sp³ cross coupling for a variety of terminal monosubstituted olefins with aryl electrophiles using Pd and CuH catalysis. In addition to its applicability to a range of aryl bromide substrates, this process was also suitable for electron-deficient aryl chlorides, furnishing higher yields than the corresponding aryl bromides in these cases. The optimized protocol does not require the use of a glovebox and employs air-stable Cu and Pd complexes as precatalysts. A reaction on 10 mmol scale further highlighted the practical utility of this protocol. Employing a similar protocol, a series of cyclic alkenes were also examined. Cyclopentene was shown to undergo efficient coupling under these conditions. Lastly, deuterium-labeling studies indicate that deuterium scrambling does not take place in this sp²-sp³ cross coupling, implying that β-hydride elimination is not a significant process in this transformation.     

Application of Suzuki Cross‐Coupling Reaction Catalyzed by Ligandless Palladium Chloride in the Synthesis of Liquid Crystals

Palladium chloride–catalyzed Suzuki cross‐coupling reaction was applied to the preparation of highly pure multiring liquid crystals with a biphenyl unit. The optimal reaction condition is the combination of 0.5 mol% PdCl₂, pyridine, and K₃PO₄, which was able to catalyze the cross‐coupling of substituted aryl bromides with substituted trans‐cyclohexylphenylboronic acids to give pure products in 38–87% yields.     

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.     

Copper‐ and Amine‐Free Sonogashira Reaction of N,N‐Disubstituted Propargylamine: Synthesis of Substituted Aryl Propargylamine

A copper‐ and amine‐free Sonogashira reaction of N,N‐disubstituted propargylamine (DEP) is reported. The procedure was mild and tolerated a series of aryl bromides, affording the substituted aryl propargylic amines in good to excellent yield.     

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.     

Copper bis(2,2,6,6-Tetramethyl-3,5-heptanedionate)–Catalyzed Coupling of Sodium Azide with Aryl Iodides/Boronic Acids to Aryl Azides or Aryl Amines

This work reports an efficient protocol for the coupling reaction of aryl iodides/boronic acids with sodium azide to aryl azides/amines in the presence of copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) Cu(TMHD)₂ catalyst. The Cu(TMHD)₂ catalyst is a structurally well-defined, O-containing, air- and moisture-stable, transition-metal complex and works at mild reaction conditions. It was observed that aryl azides can be reduced further to corresponding aniline derivatives using the same catalyst under basic reaction conditions for a prolonged period.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Application of Polymer‐Supported Triphenylphosphine and Microwave Irradiation to the Palladium‐Catalyzed Cyanation of Aryl Triflates

A variety of aryl nitriles were prepared in excellent yield from the palladium(II) acetate–catalyzed cross‐coupling of aryl triflates and zinc cyanide under microwave irradiation conditions. To facilitate purification, polymer‐supported triphenylphosphine was used as the palladium ligand. Comparison to the corresponding thermal conditions revealed much shorter reaction times with comparable yields.     

First Example of Transition‐Metal‐Free Glaser‐Type Coupling Reaction

In the presence of potassium tert‐butoxide and in toluene, 1,1‐dibromo‐1‐alkenes smoothly generated the corresponding Glaser‐type coupling‐reaction products (1,3‐diynes) in moderate to good yields.     

ZnBr2‐Catalyzed Efficient Oxidative Homo Coupling of Aryl Magnesium Bromides

Oxidative homo coupling of various arylmagnesium bromides in the presence of ZnBr₂ gave the corresponding symmetrical biaryls in moderate to good yields at room temperature. An efficient method under mild conditions without the use of reoxidant is described.     

Palladium‐Catalyzed Kumada Reaction Employing Aminophosphine as Ligand

In this article a palladium‐catalyzed Kumada reaction was reported. The procedure was mild and tolerated a series of aryl bromides, affording the biaryls in good to excellent yield.     

L ‐Proline‐Promoted CuI‐Catalyzed C‐S Bond Formation between Aryl Iodides and Thiols

An improved, mild procedure for the CuI‐catalyzed coupling reactions of aryl iodides with aliphatic and aromatic thiols, using L ‐proline as the ligand, is reported. This procedure is noteworthy given its high generality and exceptional level of functional group toleration.