Coupling Of Arylboronic Acids Research Articles

Mechanochemical aerobic oxidative Heck coupling by polymer-assisted grinding: cyclodextrin additive facilitating regioselectivity control

A novel approach utilizing the polymer-assisted grinding (POLAG) technique to facilitate the regioselective oxidative Heck coupling of aryl boronic acids with electronically unbiased olefins under solvent-free conditions was presented.

Carbonylative Coupling of Aryl Boronic Acids by Pd NPs within Melamine Dendron and Fibrous Nano-Silica

Carbonylative Coupling of Aryl Boronic Acids by Pd NPs within Melamine Dendron and Fibrous Nano-Silica

Metal-Free Reductive C–C-Coupling between Arylboronic Acids and 2-(5-Iodo-1,2,3-triazol-1-yl)phenols

A new method has been developed for the synthesis of 2-(1-arylalkyl)-1,3-benzoxazoles by coupling of arylboronic acids with 2-(5-iodo-1H-1,2,3-triazol-1-yl)phenols. The proposed cascade process involves intermediate formation of 2-(1-diazoalkyl)-1,3-benzoxazoles and their reductive C–C coupling with arylboronic acids. The procedure requires no transition metal catalysis and provides up to 67% yield of the target products.

A Fruitful Decade of Organofluorine Chemistry: New Reagents and Reactions

A Fruitful Decade of Organofluorine Chemistry: New Reagents and Reactions

Oxidative Coupling of Aryl Boronic Acids with Aryl- and Alkylamines Via Cooperative Photoredox and Copper Catalysis

Oxidative Coupling of Aryl Boronic Acids with Aryl- and Alkylamines Via Cooperative Photoredox and Copper Catalysis

Mediator-Enabled Electrocatalysis with Ligandless Copper for Anaerobic Chan-Lam Coupling Reactions.

Simple copper salts serve as catalysts to effect C-X bond-forming reactions in some of the most utilized transformations in synthesis, including the oxidative coupling of aryl boronic acids and amines. However, these Chan-Lam coupling reactions have historically relied on chemical oxidants that limit their applicability beyond small-scale synthesis. Despite the success of replacing strong chemical oxidants with electrochemistry for a variety of metal-catalyzed processes, electrooxidative reactions with ligandless copper catalysts are plagued by slow electron-transfer kinetics, irreversible copper plating, and competitive substrate oxidation. Herein, we report the implementation of substoichiometric quantities of redox mediators to address limitations to Cu-catalyzed electrosynthesis. Mechanistic studies reveal that mediators serve multiple roles by (i) rapidly oxidizing low-valent Cu intermediates, (ii) stripping Cu metal from the cathode to regenerate the catalyst and reveal the active Pt surface for proton reduction, and (iii) providing anodic overcharge protection to prevent substrate oxidation. This strategy is applied to Chan-Lam coupling of aryl-, heteroaryl-, and alkylamines with arylboronic acids in the absence of chemical oxidants. Couplings under these electrochemical conditions occur with higher yields and shorter reaction times than conventional reactions in air and provide complementary substrate reactivity.

Cu(I)–N-heterocyclic carbene-catalyzed base free C–N bond formation of arylboronic acids with amines and azoles

Abstract A new N-heterocyclic carbene (NHC) precursor of imidazolium chloride and its corresponding Cu(I)–NHC complex 1 was synthesized. The complex 1 was found to be a highly effective catalyst for Chan-Evans-Lam coupling of arylboronic acid with amines and azoles (including imidazole, pyrazole and triazole), without addition of base at room temperature. Various substituents on three substrates can be tolerated, giving the desired coupling products in good to excellent yields (62–94%). The method is practical and offers an alternative to the corresponding copper-catalyzed Chan-Evans-Lam process for the construction of C–N bonds.

Reductive Csp2–N Coupling by PIII/PV=O–Catalysis

The preparation of (hetero)arylamines has been significantly advanced by developments in transition metal-catalyzed Csp2–N coupling (e.g., Buchwald–Hartwig, Chan–Lam, and Ullmann couplings). As a complement to these strategies, our group recently demonstrated the reductive Csp2–N coupling of arylboronic acids and nitro compounds, initially nitro(hetero)arenes and more recently nitromethane, by an organophosphorus-catalyzed method operating via PIII/PV=O redox cycling.

Dichloroimidazolidinedione‐activated one‐pot Suzuki–Miyaura cross‐coupling of phenols

AbstractThe first general method for the Suzuki‐type cross‐coupling of phenols with aryl boronic acids using dichloroimidazolidinedione (DCID) as a new reagent is presented. In the presence of DCID and Pd/metal–organic framework (MOF), coupling of aryl boronic acids with a wide range of phenols, was carried out smoothly in tetrahydrofuran (THF) at reflux conditions to afford the cross‐coupling products in good to excellent yields. The structures of all compounds were corroborated by 1H‐ and 13C‐NMR. A plausible mechanism for this type of reaction is proposed.

CuI‐catalyzed direct synthesis of diaryl thioethers from aryl boronic acids and arylsulfonyl chlorides

A CuI‐catalyzed direct coupling of aryl boronic acids with arylsulfonyl chlorides for the preparation of diaryl thioethers was developed. The reaction is initiated by a PPh3 reduction of the arylsulfonyl chloride, followed by a CuI‐catalyzed C–S coupling with an aryl boronic acid. Various arylsulfonyl chlorides can directly serve as a sulfur source in this mild and efficient reaction giving the desired products in moderate to good yields. Moreover, this practical method has also been applied to the thioetherification of aryl iodides and acetylacetones.

Electrochemically Enabled Chan-Lam Couplings of Aryl Boronic Acids and Anilines.

The Chan-Lam reaction remains a highly utilized transformation for C-N bond formation. However, anilines remain problematic substrates due to their lower nucleophilicity. To address this problem, we developed an electrochemically mediated Chan-Lam coupling of aryl boronic acids and amines utilizing a dual copper anode/cathode system. The mild conditions identified have enabled the preparation of a wide range of functionalized biarylanilines in good yields and chemoselectivities.

Base-free nickel-catalysed decarbonylative Suzuki-Miyaura coupling of acid fluorides.

The Suzuki-Miyaura cross-coupling of organoboron nucleophiles with aryl halide electrophiles is one of the most widely used carbon-carbon bond-forming reactions in organic and medicinal chemistry1,2. A key challenge associated with these transformations is that they generally require the addition of an exogenous base, the role of which is to enable transmetallation between the organoboron nucleophile and the metal catalyst3. This requirement limits the substrate scope of the reaction because the added base promotes competitive decomposition of many organoboron substrates3-5. As such, considerable research has focused on strategies for mitigating base-mediated side reactions6-12. Previous efforts have primarily focused either on designing strategically masked organoboron reagents (to slow base-mediated decomposition)6-8 or on developing highly active palladium precatalysts (to accelerate cross-coupling relative to base-mediated decomposition pathways)10-12. An attractive alternative approach involves identifying combinations of catalyst and electrophile that enable Suzuki-Miyaura-type reactions to proceed without an exogenous base12-14. Here we use this approach to develop a nickel-catalysed coupling of aryl boronic acids with acid fluorides15-17, which are formed in situ from readily available carboxylic acids18-22. This combination of catalyst and electrophile enables a mechanistic manifold in which a 'transmetallation-active' aryl nickel fluoride intermediate is generated directly in the catalytic cycle13,16. As such, this transformation does not require an exogenous base and is applicable to a wide range of base-sensitive boronic acids and biologically active carboxylic acids.

Synthesis of α-arylalkylferrocenes through cesium fluoride-promoted coupling of arylboronic acids with N-tosylhydrazones

ABSTRACTA cesium fluoride-promoted reductive coupling reaction of acylferrocene tosylhydrazones with arylboronic acids has been developed, producing highly substituted α-arylalkylferrocenes in moderate to excellent yields. The reaction employs anionic fluorine to facilitate the cleavage of C–B bond. The developed methodology demonstrates a wide substrate scope and high functional groups tolerance. Moreover, the α-arylalkylferrocenes compounds were also obtained on a multi-gram scale.

Dimeric palladium 1,2,3-triazol-5-ylidene complexes – synthesis, structure, reactivity and catalytic properties in Suzuki coupling

Palladium 1,2,3-triazol-5-ylidene dimers transform to bis(carbene) species and in Suzuki coupling conditions lose carbene via reductive elimination of a 5-aryltriazolium salt.

Synthesis of 3-aryl-1-indanones via CsF-promoted coupling of arylboronic acids with N-tosylhydrazones

Synthesis of 3-aryl-1-indanones <i>via</i> CsF-promoted coupling of arylboronic acids with <i>N</i>-tosylhydrazones

Cyclopalladation in the Periphery of a NHC Ligand as the Crucial Step in the Synthesis of Highly Active Suzuki–Miyaura Cross‐Coupling Catalysts

Starting from 2,4-dichloropyrimidine, 4-(2-dialkylamino)pyrimidinyl functionalized mesitylimidazolium chlorides are accessible in a five-step reaction sequence. Two routes leading to palladium NHC complexes derived from these ligands have been worked out: By transmetalation with the corresponding NHC-AgCl complexes, C,N-coordinated palladium(II) complexes can be obtained. Treatment of palladium dichloride with the imidazolium salts in pyridine and in the presence of K2 CO3 gives cyclometalated and thus C,C-coordinated compounds. The reactivities of all these compounds were investigated in detail as well as their performance in the catalytic Suzuki-Miyaura cross-coupling reaction. It turned out that the C,C-coordinated derivatives exhibit high catalytic activities in the coupling of arylboronic acids with aryl chlorides, which is consistent with the generally accepted mechanistic ideas on substrate activation.

Coupling of Arylboronic Acids with Isocyanides

Coupling of Arylboronic Acids with Isocyanides

Access to Perfluoroalkyl-Substituted Enones and Indolin-2-ones via Multicomponent Pd-Catalyzed Carbonylative Reactions.

A simple method for accessing perfluoroalkyl-substituted enones is described applying a four-component palladium-catalyzed carbonylative coupling of aryl boronic acids together with terminal alkynes and perfluoroalkyl iodides in the presence of carbon monoxide. A wide range of highly functionalized enones can thus be prepared in a single operation in good yields. With 2-aminophenylalkynes, an intramolecular aminocarbonylation event overrules providing the indolin-2-one framework. Finally, adaptation of the two-chamber technology expands the method to the synthesis of the aforementioned structures with 13C-isotope labeling.

Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts

We report herein a transition-metal-free coupling reaction of arylboronic acids with benzyl halides and mesylates for the construction of C(sp2)C(sp3) bonds. A unique feature of this coupling reaction is the formation regioisomers in some cases. Mechanistic studies suggest that this reaction may proceed via an unprecedented Friedel–Crafts-type reaction pathway under base conditions with the assistance of boronic acid moiety.

Copper-Catalyzed Coupling of Arylboronic Acids with Sulfonyl Azides

Copper-Catalyzed Coupling of Arylboronic Acids with Sulfonyl Azides