Hydroarylation of terminal alkynes with arylboronic acids catalyzed by low loadings of palladium

The hydroarylation reaction of terminal alkynes with arylboronic acids catalyzed by low(400 ppm) loadings of palladium has been developed. The reaction is broad in scope and high-yielding, even on multigram scale. It is suitable for the synthesis of alkenes labeled with deuterium, and for the late-stage modification of bioactive molecules.     

Regiocontrolled addition of arylboronic acids to allenes using palladium and platinum catalysts

Studies about the regiocontrolled addition of arylboronic acids to allenes using a palladium or a platinum catalyst have been described. The selectivity of the reaction can be altered by the choice of the metal reagent and base. Contrary to the formation of endo-olefinic products in the reactions using hydroxopalladium complex, predominant production of exo-olefinic products was observed by the reaction with hydroxoplatinum complex.     

Suzuki-Miyaura cross-couplings of arenediazonium tetrafluoroborate salts with arylboronic acids catalyzed by aluminium hydroxide-supported palladium nanoparticles

Suzuki-Miyaura cross-couplings of arenediazonium salts with arylboronic acids catalyzed by highly active aluminium hydroxide-supported palladium nanoparticles catalyst have been investigated for the first time. The reactions are performed at 25 °C in MeOH without any base and ligand to afford biaryls in good to excellent yields under non-anhydrous and non-degassed conditions.     

Homocoupling of arylboronic acids and potassium aryltrifluoroborates catalyzed by protein-stabilized palladium nanoparticles under air in water

Palladium nanoparticles stabilized primarily within the protein cavity of a highly thermostable Dps protein (DNA binding protein from starved cells) from the thermophilic bacterium Thermosynechoccus elongatus provide an efficient catalyst for the homocoupling of boronic acids and potassium aryltrifluoroborates in water under aerobic phosphine-free conditions. Symmetrical biaryls have been isolated in good to excellent yields. Potassium aryltrifluoroborates give similar or better results than the corresponding arylboronic acids.     

Homocoupling of arylboronic acids catalyzed by simple gold salts

A range of arylboronic acids undergo a homocoupling reaction in the presence of catalytic amount of gold salts to yield symmetrical biaryls. Alkenylboronic acids, arylboronic esters, and arylborates also participate in the gold-catalyzed homocoupling reaction.     

The coupling of arylboronic acids with nitroarenes catalyzed by rhodium

The coupling of arylboronic acids with electron-deficient nitroarenes was realized for the first time by using a rhodium(I) catalyst under an air atmosphere, achieving unsymmetrical diaryl ethers with yields ranging from poor to good. From a deuterium labeling experiment, the oxygen atom is derived from ambient water. The efficiency of this reaction was demonstrated by its compatibility with fluoro, bromo, chloro, and trifluoromethyl groups.     

Remarkable co-catalysis by copper(I) oxide in the palladium catalyzed cross-coupling of arylboronic acids with ethyl bromoacetate

Copper(I) oxide can effectively co-catalyze the Suzuki type cross-coupling reactions of arylboronic acids with ethyl bromoacetate. As an alternative protocol for introducing the methylenecarboxy group into functionalized molecules, this reaction occurs in the absence of highly toxic thallium compounds or special ligands and should be convenient and practical.     

Diastereoselective synthesis of arylglycine derivatives by cationic palladium(II)-catalyzed addition of arylboronic acids to N-tert-butanesulfinyl imino esters

A cationic palladium-complex-catalyzed addition of arylboronic acids to N-tert-butanesulfinyl iminoacetates to yield the optically active arylglycine derivatives with moderate to good yield and high diastereoselectivity was developed. This reaction provides a convenient and efficient method for the synthesis of arylglycine derivatives.     

Copper salt catalyzed addition of arylboronic acids to azodicarboxylates

The addition of arylboronic acids 1 to azodicarboxylates 2 in the presence of a catalytic amount of a copper salt under mild reaction conditions gives aryl-substituted hydrazines 3 in high yields. The reaction is tolerant of a wide variety of functional groups.     

Rhodium-benzimidazolidin-2-ylidene catalyzed addition of arylboronic acids to aldehydes

Six rhodium–carbene complexes (2a–f) have been prepared and the new compounds characterized by C, H, N analyses, ¹H-n.m.r. and ¹³C-n.m.r. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of rhodium(I)–carbene complex, RhCl(COD)(1,3-dialkylbenzimidazolidin-2-ylidene), (2a–f), to give the corresponding aryl secondary alcohols in good yields.     

Polar,non-coordinating ionic liquids as solvents for the alternating copolymerization of styrene and CO catalyzed by cationic palladium catalysts

The palladium-catalyzed copolymerization of styrene and CO in an ionic liquid solvent, 1-hexylpyridinium bis(trifluoromethanesulfonyl)imide, gave improved yields and increased molecular weights compared to polymerizations run in methanol.     

Palladium‐catalyzed arylation of arylglyoxals with arylboronic acids

A palladium‐catalyzed coupling‐type reaction of arylglyoxals with arylboronic acids was achieved by use of trimesitylphosphine as the ligand and K₂CO₃ as base in toluene, providing symmetrical and unsymmetrical benzil derivatives with yields ranging from moderate to excellent. Of particular mention, the rigorous exclusion of air and moisture is not required in these transformations. Copyright © 2009 John Wiley & Sons, Ltd.     

Microwave promoted Suzuki reactions between aroyl chlorides and boronic acids catalyzed by heterogeneous and homogeneous phosphine-free palladium catalysts

Suzuki cross-coupling reactions between arylboronic acids and aroyl chlorides with phosphine-free palladium catalysis under microwave irradiation were performed to obtainment of aromatic ketones in good yields within short times. Heterogeneous and homogeneous catalysts were studied as well as their influence in the reaction selectivity relative to homocoupling of the boronic acids.     

Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform

Arylboronic acids react with aldehydes and α,β-unsaturated carbonyl compounds in the presence of a base and a catalytic amount of a palladium(0) complex with chloroform, affording the corresponding addition products in good yields, and chiral benzhydrol was obtained with up to 43% e.e. using (S,S)-bppm as a ligand. General palladium complexes have no catalytic activity without chloroform. Because chloroform is essential for this reaction, these reactions would be promoted by dichloromethylpalladium(II) species.     

Asymmetric addition of arylboronic acids to glyoxylate catalyzed by a ruthenium/Me-BIPAM complex

The enantioselective synthesis of α-hydroxy esters by ruthenium-catalyzed 1,2-addition of arylboronic acids to tert-butyl glyoxylate is described. The use of RuCl(2)(PPh(3))(3) with (R,R)-Me-BIPAM gave optically active mandelic acids of up to 99% ee. Addition of a fluoride salt such as potassium fluoride (KF) or caesium fluoride (CsF) was effective for achieving high enantioselectivities.     

Cationic palladium complex catalyzed highly enantioselective intramolecular addition of arylboronic acids to ketones. A convenient synthesis of optically active cycloalkanols

An efficient and convenient synthesis of optically active cycloalkanols by utilizing the chiral cationic palladium complex as the catalyst was achieved in mild conditions with high yield and high enantioselectivity.     

Homocoupling of arylboronic acids catalyzed by dinuclear copper(I) complexes under mild conditions

An efficient protocol for C–C coupling has been developed using three iodo-bridged copper(I) complexes as catalysts. Complexes [CuI(bpy)]₂ (1), [CuI(phen)]₂·DMF (2), and [CuI(Mephen)]₂ (3) were successfully synthesized via solvothermal method (bpy = 2,2′-dipyridyl, phen = 1,10-phenanthroline, and Mephen = 2,9-dimethylphenanthroline). The self-coupling reaction of phenylboronic acid was selected as a model reaction to evaluate the catalytic property of the complexes. Moreover, this method tolerates various substituents on the arylboronic acids such as halogens, carbonyls, and nitro groups. It shows that the iodo-bridged Cu(I) center serves as the active site to activate molecular oxygen during the catalytic process. The result illustrates that these complexes were found to be excellent catalysts for self-coupling of arylboronic acids under mild conditions.

     

Palladium catalyzed synthesis of mandelate derivatives from arylboronic acids and glyoxylate hemiacetals

NHC-coordinated cyclometalated palladium(II) catalyzed addition of arylboronic acids to methyl 2-hydroxy-2-methoxyacetate gave corresponding various functionalized methyl mandelate derivatives in good yields.     

Cyclopalladated complexes catalyzed addition of arylboronic acids to aldehydes in neat water

Cyclopalladated ferrocenylimine complexes gave high yields for the addition of arylboronic acids with aldehydes in neat water using a weak acid as additive.