Synthesis of aryloxyazetidine derivatives by CuI/l-proline catalyzed coupling reaction of arylboronic acid with 1-Boc-3-iodoazetidine

A novel CuI/l-proline catalyzed coupling reaction of 1-Boc-3-iodoazetidine with various arylboronic acids which produced aryloxyazetidine derivatives in moderate to good yields was investigated.     

Highly enantioselective rhodium-catalyzed conjugate addition of arylboronic acids to enones at room temperature

The rhodium-phosphoramidite-catalyzed asymmetric conjugate addition of arylboronic acids to enones proceeds at room temperature using [Rh(OH)(cod)]₂ or [RhCl(cod)]₂/KOH as stable and readily available catalyst precursors.     

Metal-free synthesis of substituted phenols from arylboronic acids in water at room temperature

A convenient,efficient and practical metal-free method for the synthesis of substituted phenols from arylboronic acids has been developed.The protocol uses hydrogen peroxide as a hydroxylating agent ammonium bicarbonate as an additive,and the reactions were conveniently performed in water at room temperature.The method shows an excellent tolerance of functional groups,so it will find a wide variety of applications in academic and industrial research.     

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.     

Mn/Cu catalyzed addition of arylboronic acid to nitriles: Direct synthesis of arylketones

A direct and efficient synthesis of arylketones via arylboronic acid addition to nitriles in presence of inexpensive Mn/Cu catalytic system is reported. The use of non-precious Mn and Cu salts has been found to be highly advantageous both in terms of accessibility as well as cost effectiveness. A series of arylboronic acids as well as nitriles were used to synthesize a variety of symmetrical and unsymmetrical arylketones. Based on the literature studies, the reaction mechanism is anticipated to go through an aryl radical intermediate which reacted with the copper activated nitrile to give the desired arylketones after the hydrolysis of the imine intermediate.     

A practical method for preparation of phenols from arylboronic acids catalyzed by iodopovidone in aqueous medium

A novel and efficient strategy for the ipso-hydroxylation of arylboronic acids to phenols has been developed using inexpensive, readily available, air-stable water-soluble povidone iodine as catalyst and aqueous hydrogen peroxide as oxidizing agent. The reactions were performed at room temperature under metal-, ligand- and base-free condition in a short reaction time. The corresponding substituted phenols were obtained in moderate to good yields by oxidative hydroxylation of arylboronic acids in aqueous medium.     

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.     

Convenient,metal-free ipso-nitration of arylboronic acids using nitric acid and trifluoroacetic acid

A feasible protocol for the direct ipso-nitration of arylboronic acids using trifluoroacetic acid and nitric acid as nitration reagent has been developed. Various aromatic nitro compounds are produced in moderate to good yields under the metal-free conditions. The method is operationally simple and regioselective, and might have potential application in industry.     

Acid catalyzed Knoevenagel condensation of thiobarbituric acid and aldehyde at room temperature

Abstract

Knoevenagel reactions have been performed by the action of various unsymmetrical thiobarbituric acids containing activated methylene carbon and electron deficient center of aromatic aldehydes using small amount of acetic acid as initiator in ethanolic medium. The present protocol proceeded smoothly on room temperature stirring using ethyl alcohol as solvent with the help of initiator. The work-up procedure is very simple and products have been purified by simple recrystallization. Thus rendering the methodology is good and all synthesized molecules were characterized by ¹H, ¹³C NMR, and MS spectra.     

A three-component synthesis of homoallylic amines catalyzed by CuI

Cuprous iodide is a very effective catalyst for the three-component condensation of an aldehyde, benzylamine and allyltributylstannane in DMF to produce homoallylic amines in high yields.     

Efficient allylation of aldehydes with allyltributylstannane catalyzed by CuI

Cuprous iodide has been found to be a very effective catalyst for allylation of aldehydes with allyltributylstannane. The catalytic system efficiently promotes the allylation reaction in DMF to produce homoallylic alcohols in high yield.     

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.     

A mild conversion of arylboronic acids and their pinacolyl boronate esters into phenols using hydroxylamine

Hydroxylamine was found to be a mild reagent for conversion of arylboronic acids and their pinacolyl boronate esters into phenols. This procedure works on most arylboronic acids at room temperature, yielding phenols in moderate to good yields, and efficiently on arylboronates also yielding phenols in good yields.     

Study of CuI catalyzed coupling reactions of aryl bromides with imidazole and aliphatic amines under microwave dielectric heating

Amination of a variety of functionalized aryl bromides with imidazole and primary and secondary amines was accomplished using a CuI/amino acid catalyst system under microwave heating. Application of microwave irradiation shortened the reaction time from 25–40 h to 6–20 min. Good to very good yields of the corresponding coupling products were obtained when imidazole and secondary amines were used as starting materials. In case of primary amines, the outcome of the reaction was dependent on the character of the substituent on aryl bromide.     

Generally applicable and efficient oxidative Heck reaction of arylboronic acids with olefins catalyzed by cyclopalladated ferrocenylimine under base- and ligand-free conditions

A mild and efficient method for oxidative Heck-type reaction of arylboronic acids with olefins catalyzed by cyclopalladated ferrocenylimine was developed. The results represent the first examples involving the palladacycle as the catalyst for such couplings. Moreover, the catalytic system could tolerate various functional groups, such as F, Cl, Br, NO₂ and CH₃O, and the substrates could be extended to a wide range of olefins from acrylic esters, α,β-unsaturated ketones to alkenes. Furthermore, the olefination could proceed well under base- and ligand-free conditions and employ oxygen as the environmentally benign oxidant.     

First preparation of a novel polyol resin for purifying arylboronic acids

A novel polystyrene-supported triol resin was first prepared by reaction of the Merrifield resin with trometamol.Using this resin, arylboronic acids were efficiently isolated and purified through a "capture-release" procedure in organic solvents.However,in basic aqueous solvents arylboronic acids were immobilized on the resin only with low yield.     

Facile syntheses of homoleptic diarylmercurials via arylboronic acids

A general procedure for the syntheses of diarylmercurials is presented. Reactions proceeded in isopropanol in the presence of a base and arylboronic acid. With one exception, all reactions proceeded in good to excellent yields, and this procedure was applicable to a variety of aromatic and heteroaromatic boronic acids. Products were characterized by multinuclear NMR spectroscopy and microanalysis, and investigated by DFT calculations. The structure of di(4-pyridyl)mercury (6) was further authenticated by X-ray crystallography. Combined with previous work on the formation of arylgold(I) complexes via arylboronic acids, this procedure may be generally useful for the arylation of late transition metals.     

An efficient and chemoselective Cbz-protection of amines using silica-sulfuric acid at room temperature

A simple, facile, and chemoselective N-benzyloxycarbonylation of amines using silica-sulfuric acid that proceeds under solvent-free conditions at room temperature has been achieved. These reactions are applicable to a wide variety of primary (aliphatic and cyclic) secondary amines, amino alcohols, and heterocyclic amines.     

Nickel salt-catalyzed addition reaction of arylboronic acids to aromatic aldehydes

Arylation reaction of aromatic aldehydes with arylboronic acids proceeded smoothly in the presence of a base and catalytic amount of a nickel salt, Ni(ClO₄)₂·6H₂O, in toluene/IPA = 5:1 or IPA to afford corresponding diarylmethanols in good to excellent yields.