Suzuki-type Cross-coupling Reaction Research Articles

Pd-catalyzed Suzuki-type cross-coupling of 2-pyridyl carbamoyl fluorides.

We describe a palladium-catalyzed Suzuki-type cross-coupling reaction of 2-pyridyl carbamoyl fluorides with boronic acids, which provides entry to medicinally relevant pyridyl amides. Mechanistic studies, including the synthesis and reactivity of carbamoyl Pd-F complexes, reveal the importance of both the fluoride electrophile and nitrogen directing group for aiding reactivity.

In situ palladium-doped conjugated polymer network for visible light and natural sunlight-driven Suzuki type cross-coupling reaction at room temperature

An in situ Pd doped conjugated polymer network-based efficient photocatalyst has been developed to carry out Suzuki type cross coupling reaction under visible light or sunlight.

The Preparation of Diaryl Sulfoxinium Triflates and Their Application in Palladium-Catalyzed Cross-Coupling Reactions.

Treatment of N-methyl-S,S-diaryl sulfoximines with methyl trifluoromethanesulfonate provides bench-stable sulfoxinium salts in excellent yields. Applying them in Sonogashira-, Heck- and Suzuki-type cross-coupling reactions leads to the corresponding products by sequential C-S bond cleavage and C-C bond formation. Electronic factors induced by substituents on the S-aryl groups govern the coupling efficiency.

Borylated Cymantrenes and Tromancenium Salts with Unusual Reactivity.

In continuation of our study of the chemistry of cationic (cycloheptatrienyl)(cyclopentadienyl)manganese(I) sandwich complexes, so-called “tromancenium” salts, we report here on their boron-substituted derivatives focusing on useful boron-mediated synthetic applications. Transmetalation of lithiated tricarbonyl(cyclopentadienyl)manganese (“cymantrene”) with boric or diboronic esters affords monoborylated cymantrenes that are converted by advanced high-power LED photosynthesis followed by oxidation with tritylium to their 8-boron-substituted tromancenium complexes. These new functionalized tromancenium salts are fully characterized by 1H/11B/13C/19F/55Mn NMR, IR, UV–vis, HRMS spectroscopy, single-crystal structure analysis (XRD) and cyclic voltammetry (CV). IR spectra were thoroughly analyzed by density functional theory (DFT) on the harmonic approximation in qualitative agreement of calculated vibrations with experimental values. Uncommon chemical reactivity of these borylated tromancenium salts is observed, due to the strongly electron-withdrawing cationic tromancenium moiety. No Suzuki-type cross-coupling reactions proved so far achievable, but unusual copper-promoted amination with sodium azide under microwave irradiation is possible. Diazoniation of aminotromancenium affords an extremely reactive dicationic tromanceniumdiazonium salt, which is too labile for standard Sandmeyer reactions, in contrast to analogous chemistry of cobaltocenium salts. Overall, borylated tromancenium salts display unexpected and intriguing chemical properties with the potential for novel synthetic applications in future work.

Catalytic reductive ring opening of epoxides enabled by zirconocene and photoredox catalysis

Catalytic reductive ring opening of epoxides enabled by zirconocene and photoredox catalysis

Unlocking the Friedel-Crafts arylation of primary aliphatic alcohols and epoxides driven by hexafluoroisopropanol

Unlocking the Friedel-Crafts arylation of primary aliphatic alcohols and epoxides driven by hexafluoroisopropanol

Synthesis and application of SBA-Pr-Py@Pd in Suzuki-type cross-coupling reaction

Synthesis and application of SBA-Pr-Py@Pd in Suzuki-type cross-coupling reaction

A comparative study on Suzuki-type 11 C-methylation of aromatic organoboranes performed in two reaction media.

The Suzuki-type cross coupling reaction is a palladium-mediated multistep reaction that has been used to synthesize several 11 C-labeled tracers for PET. However, the impact of the selected organoborane reagent and reaction medium on the radiochemical yield (RCY) has not been thoroughly investigated. To bridge this gap, we studied the synthesis of 1-[11 C]methylnaphthalene using four different organoborane precursors in reactions performed in DMF/water and THF/water. In the synthesis of 1-[11 C]methylnaphthalene, the best radiochemical yields (RCYs), approximately 50%, were obtained with boronic acid and pinacol ester precursors, whereas less than 4% RCY was obtained when performing the reaction with the N-methylimidodiacetic acid boronic ester (MIDA ester) precursor. 1-[11 C]methylnaphthalene was obtained in higher yields in almost all syntheses performed in THF/water as compared to DMF/water. This observation was in line with previously reported results for [11 C]UCB-J, a tracer for the synaptic vesicle glycoprotein 2A (SV2A) receptor, that also was obtained in higher RCY when synthesized in THF/water. The same trend was observed with [11 C]cetrozole, where the RCY was more than doubled in THF/water compared to the previously published synthesis performed in DMF. These results suggest that THF/water could be the preferred reaction medium when producing PET tracers via the Suzuki-type coupling reaction.

Base-free Ni-catalyzed Suzuki-type cross-coupling reactions of epoxides with boronic acids.

A Ni-catalyzed Suzuki-type cross-coupling of boronic acids with epoxides without an exogenous base and with broad substrate scope has been developed. The product selectivity of styrenyl epoxides is different from that of previous work. This methodology uses readily available starting materials to access a range of substituted alcohols, which are valuable feedstock chemicals.

A novel zinc-catalyzed Suzuki-type cross-coupling reaction of aryl boronic acids with alkynyl bromides

A novel Suzuki-type cross-coupling reaction of organoboron reagents with alkynyl bromides has been developed in the presence of catalytic Et2Zn/DMEDA system. The reaction afforded a variety of internal alkynes in moderate to excellent yields under mild reaction conditions without the formation of any homo-coupling products. The resulting internal alkynes have valuable applications in pharmaceutical and industrial areas. The use of relatively non-toxic zinc, chelating amine ligand and low reaction temperature make this protocol an alternative for the synthesis of internal alkynes. The scope and limitations of this protocol are also investigated.

Suzuki-Type Cross-Coupling Reaction of Unprotected 3-Iodoindazoles with Pinacol Vinyl Boronate: An Expeditive C-3 Vinylation of Indazoles under Microwave Irradiation.

Herein we report an expeditive C-3 vinylation of unprotected 3-iodoindazoles under microwave irradiation. Ten C-5 substituted 3-vinylindazole derivatives, nine of them novel, were synthesized through this method, which proceeds in moderate to excellent yields starting from C-5 substituted 3-iodoindazole derivatives. In all cases, the C-3 vinylated derivative was the only isolated product. This methodology allows access to 3-vinylated indazoles selectively and directly without the need of N-protection. 3-Vinylindazoles could be interesting synthetic intermediates allowing access to biologically active molecules.

First application of homogeneous Pd nanoparticles prepared by pulsed laser ablation in liquid to a Suzuki-type reaction

Palladium nanoparticles are a valuable alternative to molecular catalysts for not requiring costly and toxic ligands. In this study palladium nanoparticles were produced by either pulsed laser ablation in liquid or direct reactions between ascorbic acid and a palladium salt. The obtained nanoparticles have been characterized by TEM, XRD and XPS techniques and they have been applied to the catalysis of the ligand-free Suzuki-type cross-coupling reaction. Methyl (E)-4-bromocrotonate has been coupled to different aryl and heteroarylboronic acids with yield up to 81% and selectivity between 85 and 90%. Investigations on catalytic reusability of the NPs have shown that they could be used for three or ten catalytic cycles without loss of activity, respectively for LAL or chemically synthesized Pd NPs.

Transition metal-free Suzuki type cross-coupling reaction for the synthesis of dissymmetric ketones

A simple, efficient and metal-free route for the synthesis of dissymmetric ketones through Suzuki type cross-coupling reaction has been established. This strategy signifies an attractive, cost-effective and operationally convenient tool for the synthesis of a wide range of dissymmetric ketones. Although conventional routes for the synthesis of ketones have been widely used, the potential challenge with these methods is functional group tolerance. The reported metal-free method represents a reaction with moderate functional group tolerance. The procedure is operationally convenient and shows broad substrate scope with good to excellent product yields.

A supramolecular ensemble of a PBI derivative and Cu2O NPs: potential photocatalysts for the Suzuki and Suzuki type coupling reactions

The in situ generated supramolecular ensemble (2:Cu2O) of Cu2O NPs and aggregates of PBI derivative 2 exhibited excellent photocatalytic efficiency in the Suzuki–Miyaura and Suzuki type cross-coupling reactions under mild and eco-friendly conditions.

Catalytic Suzuki couplings by an amido pincer complex of palladium

The catalytic feasibility of [PNP]PdCl, where [PNP]- = bis(2-diphenylphosphinophenyl)amide, on biaryl syntheses from Suzuki-type cross-coupling reactions is demonstrated. A number of electronically activated, unactivated, and deactivated (hetero)aryl bromides and iodides is viable to react with arylboronic acids. Of particular note of this catalysis is its success in the high yield production of sterically encumbered tri-ortho-substituted biaryls and its operative compatibility under aerobic conditions in aqueous solutions.

Aggregates of the pentacenequinone derivative as reactors for the preparation of Ag@Cu2O core-shell NPs: an active photocatalyst for Suzuki and Suzuki type coupling reactions.

Aggregates of the pentacenequinone derivative 1 act as reactors and stabilizers for rapid and facile preparation of Ag@Cu2O core-shell nanoparticles (NPs) in aqueous medium. The in situ generated Ag@Cu2O core-shell hybrid materials enabled efficient visible light harvesting to catalyse the palladium free Suzuki-Miyaura and Suzuki type cross coupling reactions at room temperature.

Synthesis of Metallo-Supramolecular Polymers Using 5,5′-Linked Bis(1,10-Phenanthroline) Ligands

5,5′-Linked bis(1,10-phenanthroline)s were synthesized as new bidentate ligands by a palladium-catalyzed Suzuki-type cross-coupling reaction. Coordination of the ligands to Cu(II), Ni(II), Ag(I), and Zn(II) ions resulted in metallo-supramolecular polymer formation. The 1:1 complexation of the ligands and the metal ions was confirmed by UV-vis titration experiments. The high molecular weights of more than 10⁵ Da, caused by the high complexation constants, were confirmed by the SEC-Viscometry-RALLS method.

PdCl2-catalyzed cross-coupling reaction of arylacetylene iodides with arylboronic acids to diarylacetylenes

Anew Suzuki-type cross-coupling reaction between 1-iodo-2-arylalkynes and arylboronic acids to afford a wide variety of functionalized diarylacetylenes in a mild reaction condition was developed. The reaction was catalyzed by a small amount of a structurally simple, commercially available, and stable PdCl2. This unique sp-sp(2) carbon-carbon bond formation provides a new protocol for the synthesis of diarylacetylenes, which is a new addition to the Suzuki cross-coupling reaction. (C) 2010 Elsevier Ltd. All rights reserved.

Benzothiazole-Based Fluorophores of Donor−π-Acceptor−π-Donor Type Displaying High Two-Photon Absorption

A series of novel heterocycle-based dyes with donor-pi-bridge-acceptor-pi-bridge-donor (D-pi-A-pi-D) structural motif, where benzothiazole serves as an electron-withdrawing core, have been designed and synthesized via palladium-catalyzed Sonogashira and Suzuki-type cross-coupling reactions. All the target chromophores show strong one-photon and two-photon excited emission. The maximum two-photon absorption (TPA) cross sections delta(TPA) of the prepared derivatives bearing diphenylamino functionalities occur at wavelengths ranging from 760 to 800 nm and are as large as approximately 900-1100 GM. One- and two-photon absorption characteristics of the title dyes have also been investigated by using density functional theory (DFT) and the structure-property relationships are discussed. The TPA cross sections calculated by means of quadratic response time-dependent DFT using the Coulomb-attenuated CAM-B3LYP functional support the experimentally observed trends within the series, as well as higher delta(TPA) values of the title compounds compared to those of analogous fluorene or carbazole-derived dyes. In contrast, the traditional B3LYP functional was not successful in predicting the observed trend of TPA cross sections for systems with different central cores. In general, structural modification of the pi-bridge composition by replacement of ethynylene (alkyne) with E-ethenylene (alkene) linkages and/or replacement of dialkylamino electron-donating edge substituents by diarylamino ones results in an increase of delta(TPA) values. The combination of large TPA cross sections and high emission quantum yields makes the title benzothiazole-based dyes attractive for applications involving two-photon excited fluorescence (TPEF).

Synthesis and preliminary characterization of novel naphthalene bisimide based copolymers

Here we report the synthesis and preliminary characterization of three novel conjugated 2,6-(naphthalene-1,4,5,8-tetracarboxylic- N, N′-dialkyldiimide) based copolymers with π-conjugation throughout the main chain. Two (PNATF and PNTTOF) copolymers were polymerized through Suzuki type cross-coupling reactions, the other (PNATT3) via a Stille-type reaction. The modifications of the side chain on the naphthalene bisimide unit and the thiophene contents in the polymer backbone were investigated. The structures of these polymers were confirmed by NMR. PNATF and PNTTOF could be dissolved in common solvents such as toluene, CHCl 3 and 1,2-dichlorobenzene. The optical spectra of the three copolymers revealed that they had two strong absorption bands at 386–394 and 600–670 nm. The photoluminescence spectra of PNATF and PNTTOF showed a weak red emission. The band gap values of the copolymer films determined from electrochemical and optical measurements were in good agreement, ranging between 1.58–1.88 and 1.53–1.69 eV, respectively. From these data we suggest these three copolymers are worthy of further investigation as potential candidates for applications in electronic devices.