Reaction Of Arylboronic Acids Research Articles

Ligand-controlled regiodivergent arylation of aryl(alkyl)alkynes and asymmetric synthesis of axially chiral 9-alkylidene-9,10-dihydroanthracenes

Transition metal-catalyzed addition of organometallics to aryl(alkyl)alkynes has been well known to proceed with the regioselectivity in forming a carbon–carbon bond at the alkyl-substituted carbon (β-addition). Herein, the reverse regiochemistry with high selectivity in giving 1,1-diarylalkenes (α-addition) was realized in the reaction of arylboronic acids with aryl(alkyl)alkynes by use of a rhodium catalyst coordinated with a chiral diene ligand, whereas the arylation of the same alkynes proceeded with the usual regioselectivity (β-addition) in the presence of a rhodium/DM-BINAP catalyst. The regioselectivity can be switched by the choice of ligands on the rhodium catalysts. This reverse regioselectivity also enabled the catalytic asymmetric synthesis of phoenix-like axially chiral alkylidene dihydroanthracenes with high enantioselectivity through an α-addition/1,4-migration/cyclization sequence.

Fe-ppm-Pd on charcoal: Palladium nanoparticles catalyzed Suzuki−Miyaura cross-coupling reactions of aryl boronic acids (aryl neopentyl-1,3-diol boronic ester) with aryl halides

A facile and readily available Fe-ppm-Pd/C catalyst has been developed for catalyzing Suzuki-Miyaura cross-coupling reactions. When combined with dicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl) phosphine (SPhos), this catalyst, with low levels of palladium (as low as 180 ppm), efficiently facilitates cross-coupling reactions between aryl boronic acids (or aryl neopentyl-1,3-diol boronic ester) and a wide range of aryl halides, including inactivated aryl chlorides. Additionally, the recovered Fe-ppm-Pd/C catalyst has demonstrated sustained catalytic activity over four runs, indicating minimal decline in performance. This suggests the catalyst's potential for long-term use and its practicality in industrial applications.

A Difluoromethylation Reagent: Access to Difluoromethyl Arenes through Palladium Catalysis.

A new radical difluoromethylation was developed by using inexpensive and readily available difluoroacetic anhydride and N-phenyl-4-methylbenzenesulfonamide for the first time. The reaction of arylboronic acids with the new difluoromethylation reagent, N-phenyl-N-tosyldifluoroacetamide, proceeded smoothly in the presence of palladium catalyst to provide difluoromethylarenes in satisfactory to excellent yields. The electronic property (electron-donating or electron-withdrawing) of the substituent linked to the aromatic ring did not considerably influence the reactivity of arylboronic acid. Various groups, including the synthetically useful functional groups Cl, CN, and NO2, were tolerated well under the current reaction conditions.

Three-Dimensional Homochiral Covalent Organic Frameworks with Intrinsic Chiral qzd Topology.

Although a variety of chiral porous framework materials have been reported, there are few examples known to combine molecular chirality, helicity, and three-dimensional (3D) intrinsically chiral topology in one structure, which is beneficial for chirality transfer and amplification. Here, we report the synthesis of the first two 3D covalent organic frameworks (COFs) with an intrinsic chiral qzd topology, which exhibit unusual integration of various homochiral and homohelical features. By imine condensation of 4-connected porphyrin tetraamines and 2-connected enantiopure diene dialdehyde, we prepared two isostructural COFs with a noninterpenetrated qzd topology. The specific geometry and conformation flexibility of the V-shaped diene linker control the alignment of square-planar porphyrin units with rotational linkages and facilitate the creation of homochiral extended porous structures that feature a helical arrangement of porphyrins. Post-synthetic metalation of CCOF 23 with Rh(I) affords a heterogeneous catalyst for the asymmetric Michael addition reaction of aryl boronic acids to 2-cyclohexenone, which shows higher enantioselectivities compared to their homogeneous counterparts, presumably due to the confined effect of helical channels. This finding will provide an impetus to explore multichirality materials, offering new insights into the generation and control of helicity, homochirality, and enantioselectivity in the solid state.

Preparation and investigation of catalytic activity of a magnetic Cu-complex immobilized on the histidine modified starch biopolymer

In the present study, at first a magnetic starch oxide support that functionalized with histidine methyl ester was prepared. Then, histidine segments were alkylated with ethyl bromide to form imidazolium salts on this magnetic biopolymer hybrid. The successful synthesis of the prepared nanocomposite was proved by various analysis contain EDX, FE-SEM, FT-IR, VSM, ICP and XRD. The catalytic amount of this nanocomposite was accelerated coupling reaction of aryl boronic acids, NaN3 and phenylacetylene for the synthesis of different 1,4-diaryl-1,2,3-triazoles with high yields at proper reaction times under mild reaction conditions.

Room temperature synthesis of β-ketonitriles catalyzed by metal–organic framework supported Pd nanoparticles

A Pd supported on a metal–organic framework catalyst has been prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray techniques. The designed heterogeneous catalyst Nd-MOF/Pd can promote the addition reaction of aryl boronic acids with dinitriles to give the corresponding β-ketonitriles in high yields at room temperature. Moreover, the catalyst can be recovered and recycled, running for five times without obvious loss of its reactivity.

Mechanochemical synthesis of biphenyl-derived organic fluorescent materials via solvent-free and ligand-free oxidative homocoupling reactions

The palladium-catalyzed solvent-free and ligand-free oxidative homocoupling reactions of aryl boronic acids via ball-milling are developed to synthesize a series of biphenyl-derived organic fluorescent materials.

Metal-free reductive c-c-coupling between arylboronic acids and 2-(5-iodo-1,2,3-triazolyl)phenols

A novel approach to 2-(1-arylalkyl)benzoxazoles via a reaction of arylboronic acids with 2-(5-iodo-1,2,3-triazolyl)phenols has been developed. The key intermediates of the proposed cascade transformation are 2-(1-diazoalkyl)benzoxazoles, entering reductive C-C-coupling with boronic acids. The reaction proceeds under transition-metal-free conditions and affords target compounds in yields up to 67%.

Pd‐catalyzed Three‐component Cross‐coupling of Arylhydrazides with Arylboronic Acids and TFBen: Facile Access to Diaryl Ketones via Denitrogenative Carbonylation

AbstractCarbonylation with CO surrogates is one of the most common methods for introduction of carbonyl groups in ketone synthesis. However, arylhydrazides have not been used as an aryl source in this denitrogenative method even though they are cheap and accessible. Here, we report development of palladium catalysis for the three‐component reactions of arylboronic acids, CO‐surrogates (benzene‐1,3,5‐triyl triformate), and arylhydrazides under oxygen conditions to produce diaryl ketones. (Hetero)arylhydrazides, as well as (hetero)arylboronic acids are suitable reaction partners, and good functional group compatibility was achieved. This method could be used for streamlined synthesis of diaryl ketones, ketoprofen and fenofibrate.

Microwave‐Assisted Silver‐Catalyzed Synthesis of Biaryl Compounds

AbstractA rapid, ligand/oxidant/base‐free, silver carbonate‐catalyzed homocoupling reaction of aryl boronic acids under microwave irradiation for the synthesis of symmetric biaryls is described here. This protocol tolerates a wide range of electron‐donating, electron‐withdrawing, and heterocyclic boronic acids to provide the corresponding biaryl products in good to excellent yields. The features of this strategy include a wide substrate scope, mild reaction conditions, high functional group tolerance, good to excellent yields, and short reaction time.

Rh(I)-Catalyzed Enantioselective Arylation of Cyclic N-Sulfonyl Diketimines Using Planar-Chiral Phosphine-Olefin Ligands Based on a (Cyclopentadienyl)manganese(I) Scaffold with a Highly Fluorinated Aryl Phosphino Group.

Catalytic enantioselective 1,2-addition reactions of arylboronic acids with 1,2,5-thiadiazoline 1,1-dioxide derivatives were achieved using planar-chiral phosphine-olefin ligand L5 with a bis[(2,3,4,5,6-pentafluoro)phenyl]phosphino group, showing ≤98% ee. The enantioselectivities of the addition products were improved by increasing the number of fluoro substituents on the aromatic ring of the ligand. X-ray crystallographic studies of 3aa and [RhCl/L5]2 revealed the absolute configuration of the enantioenriched addition product 3 and the mode of phosphine-olefin bidentate coordination of L5 to a rhodium(I) cation.

Construction and Characterization of Fe3O4-Bis[Imine-Pyridine]-Cu(OAc)2 Nanocomposite: A Novel and Ecofriendly Reusable Nanocatalyst for Click Synthesis of 1-aryl-1,2,3-Triazole Derivatives

1,2,3-triazoles exist in the structure of many natural compounds and are important because of their biological properties. Considering the high importance of these compounds in medical and biological processes, providing new, efficient and green catalytic systems for their synthesis is considered as an important challenge among synthetic chemists. Multicomponent reactions provide a shorter and more efficient method for the synthesis of natural compounds and complex molecules, especially heterocyclic compounds. During the last decade, the immobilization of metallic catalysts especially copper catalysts on the surface of magnetic nanoparticles modified with ligand has presented a nice and efficient catalytic system for the performance of chemical reactions. In this research work, we fabricated successfully Fe3O4-Bis[Imine-Pyridine]-Cu(OAc)2 nanocomposite and investigated its activity in the click synthesis of 1-aryl-1,2,3-triazole derivatives through the one-pot three-component reaction of aryl boronic acids with alkynes and sodium azide under mild conditions. The Fe3O4-Bis[Imine-Pyridine]-Cu(OAc)2 catalyst showed high activity and could be recovered and reused seven times without significant loss in catalytic activity and selectivity.

Facile synthesis of a new covalent organic nanosheet (CON-KEY1) based on polyamide links as an effective heterogeneous catalyst in C-C cross coupling reactions.

C-C coupling reactions represent a fundamental synthetic methodology widely employed in academic and industrial settings. Herein, we present a report on developing and synthesizing a heterogeneous catalyst that is environmentally compatible and has recycling capabilities. Furthermore, the utilization of this catalyst for C-C coupling reactions was explored. A novel amide-based CON was prepared via the reaction of a novel [2,2'-bipyridine]-5,5'-diamine (BDA) and 1,3,5-tris(4-carboxyphenyl) (TCB). TCB was activated with carbonyl diimidazole (CDI) and then reacted with BDA to synthesize favorable CON (i.e., CON-KEY1). Finally, the CON synthesized was reacted with palladium chloride ions, and the palladium-containing organocatalytic complex was decorated with the abbreviated Pd/CON-KEY1. This new heterogeneous complex was fully characterized through the required techniques, including FT-IR, EDX, XRD, TEM, SEM, ICP, TGA-DTA, N2 isotherms, and elemental mapping analysis. Computer simulation results include a multi-sheet 2D framework proposed by CON-KEY1. As a result, palladium ions were found to be arranged between the layers and on the CON surface. This heterogeneous complex functioned as a catalyst precursor in both the Suzuki-Miyaura coupling reaction of aryl boronic acids with aryl halides and the Heck reaction of aryl halides with acrylate derivatives or styrene. The desired coupling products with various functional groups were successfully attained with excellent yields of up to 98%. Simple set-up, improved yields, short reaction times, non-toxic solvents, catalyst durability, and high turnover frequency are among the distinct advantages of this synthetic method. Some other outstanding features of this catalytic system include convenient separation of catalysts and products, high yields, almost complete conversion, high selectivity, and good turnover frequency (TOF). The results show that the highest product efficiency in the reaction was achieved in the shortest possible time using Pd/CON-KEY1. Theoretical studies demonstrated the precedence of the palladium complexation with nitrogen atoms of CON-KEY1 rather than oxygen ones. Natural Bond Orbital (NBO) analysis affirmed that the system with Pd-N bonds (Eg = 0.089 eV) is more reactive with high electron conductivity compared to the Pd-O system (Eg = 0.120 eV).

Construction of a MOF-Supported Palladium Catalyst via Metal Metathesis.

A new MOF-supported heterogeneous palladium catalyst Pd/NBB-1 has been synthesized successfully through the effective metal metathesis between Pd(CF3 COO)2 and NBB-1. NBB-1 is a two-dimensional zinc metal-organic framework constructed from 2-aminoterephthalate (NH2 -H2 BDC) and 2,2'-bipyridine-5-carboxylate (HBPC) by solvothermal method. The replacement efficiency of Pd(II) to Zn(II) is up to 72% after only 24 hours, which is beneficial to the catalytic application. Pd/NBB-1 with a low loading of 2 mol% works efficiently in the 1,4-addition reaction of arylboronic acids with α,β-unsaturated ketones in air, and its catalytic activity keeps unchanged after 3 reaction cycles. This work provides a new strategy to effectively prepare supported noble metal/MOF catalysts, which would further increase the practical applications of metal-organic frameworks.

Highly Reactive Palladium-Catalyzed and Acetonitrile-Mediated Three-Component Reactions for Arylsulfone Synthesis.

Arylsulfone groups play an important role in the synthesis of functionalized molecules. The acetonitrile-mediated three-component reactions for arylsulfone synthesis were developed in the presence of a 0.00025 mol % palladium catalyst. Arylboronic acids reacted with potassium metabisulfite (K2S2O5) and benzyl bromide in the presence of LiF and a very low concentration of PdCl2 in acetonitrile solvents to produce the corresponding benzyl arylsulfones in moderate to good yields. Various arylboronic acids reacted with K2S2O5 and carbon electrophiles to produce the desired arylsulfones under the optimized conditions. It was proposed that acetonitrile accelerated the generation of aryl anion species from the reaction of arylboronic acids and LiF.

N-Heterocyclic carbene copper complex catalyzed Chan-Evans-Lam reactions of arylboronic acids with azoles and amines

An efficient protocol of Chan-Evans-Lam reactions involving arylboronic acids and azole and amine derivatives was developed based on a series of N-heterocyclic carbene copper (Cu-NHC) complexes as the precatalysts. The relationship between the catalyst structure and catalytic properties was investigated in detail. The results demonstrated that the modification of NHC backbone with acenaphthyl group exhibited significant beneficial effect on the coupling efficiencies. Nonetheless, it appeared that more bulk on the N-aryl moieties of NHC ligands impeded the reactions. The protocol also features mild reaction conditions, such as low catalyst loading (0.1–1 mol%), non-toxic solvent and air as the sole oxidant, which highlights the usefulness of Cu-NHC as the precatalyst for this reaction.

CuCl‐Catalyzed Conversion of Aryl Boronic Acids and Carbon Dioxide to Carboxylate Esters

AbstractThe CuCl‐catalyzed reaction of aryl boronic acid with carbon dioxide to form carboxylate ester after treatment with CH3I has been developed. The procedure featured mild conditions and good functional group tolerances. A diverse range of aryl boronic acids were effectively converted into carboxylate esters. Even those bearing sensitive groups such as carbonyl, ester, and amide could produce the desired products in good yields.

In Situ Monitoring of Transmetallation in Electric Potential-Promoted Oxidative Coupling in a Single-Molecule Junction

In Situ Monitoring of Transmetallation in Electric Potential-Promoted Oxidative Coupling in a Single-Molecule Junction

Cu(ii)-vitamin C-complex catalyzed photo-induced homocoupling reaction of aryl boronic acid in base-free and visible light conditions.

In this work, the photocatalytic efficiency of Cu(ii)–vitamin C complex immobilized on titanium dioxide nanoparticles was exploited in the photo-assisted homocoupling reaction of aryl boronic acids under heterogeneous conditions. The homocoupling reaction affords the corresponding symmetrical biaryls in 50–97% yields at ambient temperature in the air under visible light irradiation without any need for any additive such as base or oxidant. This method tolerates various substituents on the aryl boronic acids such as halogen, carbonyl, and a nitro group. The light-dependent photocatalytic performance of the title catalyst evaluated by action spectra revealed a maximum apparent quantum efficiency (AQYs) at 410 nm demonstrating the visible-light-driven photocatalytic reaction. The as-prepared nano biophotocatalyst proved to be reusable at least six times without losing its activity. Thus this work exhibits a favorable method from the environmental and economic point of view which enables the industrially important reactions such as coupling reactions, to be carried out efficiently under photocatalytic and practically attainable conditions.

Mesoporous silica-supported rhodium complexes alongside organic functional groups for catalysing the 1,4-addition reaction of arylboronic acid in water

Mesoporous silica-supported Rh complexes alongside organic functional groups enable 1,4-addition reaction in water.