Nickel-catalyzed decarboxylative coupling of an alkynyl carboxylic acid with aryl iodides

A decarboxylative coupling reaction with an alkynyl carboxylic acid and aryl iodides in the presence of a nickel catalyst was developed. When the reaction was conducted with NiCl₂ (10 mol%), Xantphos (15 mol%), Mn (1.0 equiv), and Cs₂CO₃ (1.5 equiv), the desired diaryl alkynes were formed in moderated to good yields. Furthermore, this method does not produce the diyne, which is formed in the homocoupling of alkynyl carboxylic acids.     

Palladium-catalyzed highly regioselective Heck reaction of aryl nonaflates with electron-rich olefins

Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results indicated that aryl nonaflates are effective alternative to the frequently employed aryl triflates.     

Pd-catalyzed decarboxylative couplings of arenecarboxylic acids with aryl iodides

The combination of palladium chloride with BINAP shows high efficiency in the decarboxylative cross-coupling reactions of arenecarboxylic acids with aryl iodides. The reactions proceed smoothly to generate the corresponding biaryl compounds in good to excellent yields.     

Silver-catalyzed decarboxylative halogenation of carboxylic acids

Decarboxylative halogenation of carboxylic acids catalyzed by silver carbonate is reported. ortho-Nitrobenzoic acids react with copper(II) chloride or bromide in DMF/DMSO at 130-140 °C leading to the corresponding aryl halides in moderate to good yields.     

Palladium-catalyzed highly regioselective and stereoselective arylation of electron-rich allylamines with aryl bromides

A palladium-catalyzed, highly efficient Heck arylation of electron-rich N,N-diprotected allylamine derivatives with a wide range of aryl bromides under ligand-free conditions has been developed. In the presence of Pd(OAc)₂ and an appropriate additive, the reaction proceeds with excellent regioselectivity and stereoselectivity, leading exclusively to the γ-arylated (E)-allylamine products in good to excellent yields. It was found that the choice of solvent, olefin, additive and temperature has an important influence on the reaction. Worthy of note is that good results were observed only when using N,N-diprotected allylamines containing carbamate moiety, and the steric properties of allylamines also have important impacts on the regiocontrol. The use of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) or HQ (hydroquinone) as the additive is also crucial for securing a faster reaction rate. This method provides a straightforward approach for the efficient synthesis of various γ-arylated, linear (E)-allylamines.     

Palladium-catalyzed decarboxylative coupling of benzoic acid derivatives using hydrazone ligands

Palladium-catalyzed decarboxylative coupling of benzoic acid derivatives with arylboroxins gave biaryls using a catalytic amount of Pd(TFA)₂–hydrazone 1d system with Ag₂CO₃ at 80 °C in good yields. We also found that decarboxylative coupling with aryl(trialkoxy)silanes gave biaryls using a Pd(TFA)₂–hydrazone 1g system with AgF in good yields.     

Copper-mediated direct arylation of benzoazoles with aryl iodides

The direct arylation of 1,3-benzoazole compounds with aryl iodides is effectively promoted by CuI with use of PPh₃ and Na₂CO₃ or K₃PO₄ as ligand and base, respectively, in DMF or DMSO to produce the corresponding 2-arylated products with good yields.     

Metal-free synthesis of aryl esters by coupling aryl carboxylic acids and aryl boronic acids

A facile synthesis of aryl esters is developed by coupling aryl carboxylic acids and aryl boronic acids in the presence of PhI(OAc)₂ and carbonyl diimidazole. A wide range of functional groups were tolerant to the metal-free reaction condition that led to the desired products in good yields.     

C-H arylation of unactivated arenes with aryl halides catalyzed by cobalt porphyrin

A general procedure for cobalt-catalyzed direct C-H arylation of unactivated arenes has been discovered. This method employs aryl halides as the direct coupling partners with arenes without using any Grignard-type reagents. This catalysis opens a new methodology for the preparation of symmetrical as well as unsymmetrical biaryls in a user-friendly approach.     

Palladium-catalyzed intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides

Give me a ring? An efficient approach has been developed for the intramolecular decarboxylative coupling of arene carboxylic acids/esters with aryl bromides catalyzed by palladium (see scheme). From a synthetic viewpoint, this method is highly attractive because the catalyst loading is low, the optimized reaction conditions are mild, and the substrate scope is broad.     

Pd-catalyzed decarboxylative cross-coupling of sodium pyrimidinecarboxylates with (hetero)aryl bromides

A straightforward method for the synthesis of functionalized 4- or 5-(hetero)arylpyrimidines via decarboxylative cross-coupling reaction from readily available pyrimidine-4- and pyrimidine-5-carboxylates was described. In the presence of dual-catalyst system of Pd(PPh₃)₄/Cu₂O, the reaction proceeds smoothly, tolerates a variety of functional groups, and provides easy access to the synthesis of different (hetero)arylpyrimidines compounds.     

Palladium-catalyzed direct C-H arylation of unactivated arenes with aryl Halides

An efficient palladium-catalyzed direct C-H arylation of unactivated arenes has been discovered. This method employs aryl halides as the direct coupling partners with arenes without using any external ligands. This catalysis opens a new methodology for the preparation of symmetrical as well as unsymmetrical biaryls in a user-friendly approach.     

Synthesis of symmetrical diarylalkyne from palladium-catalyzed decarboxylative couplings of propiolic acid and aryl bromides under water

Symmetric diarylalkynes were obtained from the decarboxylative coupling reactions of aryl bromides and propiolic acid in water solvent condition. In the presence of phase transfer surfactant C₁₈H₃₇N(CH₃)₃Cl, the catalytic system of both Pd(PPh₃)₂Cl₂/dppb and Pd(TPPMS)₂Cl₂/TPPMS afforded the desired coupled products in good yields.     

Nickel catalyzed decarboxylative alkylation of aryl triflates with anhydrides

Aliphatic acid anhydrides are the versatile building blocks and the new method for the conversion of anhydrides is thus of great significance. Herein, we report the decarboxylative alkylation of aryl triflates with aliphatic acid anhydrides via nickel catalysis. This novel method provides a facile access to construct Csp²-Csp³ bond. In addition, this method is compatible with a broad array of functional groups and exhibits good substrates scope.     

Transition-metal-free highly chemo- and regioselective arylation of unactivated arenes with aryl halides over recyclable heterogeneous catalysts

A novel heterogeneous catalysis system using metal-organic frameworks as catalyst demonstrated excellent chemo- and regioselectivity for the direct arylation of unactivated arenes with aryl iodides/bromides without the assistance of any transition metals.     

Cu-catalyzed decarboxylative iodination of aryl carboxylic acids with NaI: A practical entry to aryl iodides under aerobic conditions

A simple and practical Cu-catalyzed decarboxylative iodination has been well established under aerobic condition, which provides a useful method to synthesize aryl iodides in moderate to good yields with the use of (hetero)aryl carboxylic acids and NaI as starting materials. Thiabendazole has been prepared via a three-step procedure to show synthetic practicability of the protocol.     

Palladium-catalyzed direct C2-arylation of free (NH) indoles via norbornene-mediated regioselective CH activation

A palladium-catalyzed direct C2-arylation reaction of free (NH) indoles has been developed. This reaction relies on a norbornene-mediated CH activation process on the indole ring, which features high regioselectivity and excellent functional group tolerance.     

Ionic liquid-promoted, highly regioselective Heck arylation of electron-rich olefins by aryl halides

Palladium-catalyzed regioselective Heck arylation of the electron-rich olefins, vinyl ethers 1a-d, enamides 1e-g, and allyltrimethylsilane 1h, has been accomplished in imidazolium ionic liquids with a wide range of aryl bromides and iodides instead of the commonly used, but commercially unavailable and expensive, aryl triflates. The reaction proceeded with high efficiency and remarkable regioselectivity without the need for costly or toxic halide scavengers, leading exclusively to substitution by aryl groups of diverse electronic and steric properties at the olefinic carbon alpha to the heteroatom of 1a-g and beta to the heteroatom of 1h. In contrast, the arylation reaction in molecular solvents led to mixtures of regioisomers under similar conditions. Several lines of evidence point to the unique regiocontrol stemming from the ionic environment provided by the ionic liquid that alters the reaction pathway. The chemistry provides a simple, effective method for preparing branched, arylated olefins and contributes to the extension of Heck reaction to a wider range of substrates.     

Palladium-catalyzed benzylic direct arylation of benzyl sulfones with aryl halides

An effective palladium catalyst system for the direct arylation of benzyl sulfones with aryl halides has been developed. The catalytic reaction provides a facile route to diarylmethyl sulfones. The products can be transformed further via desulfonylative functionalization mediated by aluminum compounds.