Suzuki Coupling Research Articles

Thienothiophene and biphenyl based conjugated porous polymer as a photocatalyst for visible light induced free radical and cationic polymerization

Over the last few decades, photopolymerization has been the center of great attention owing to a variety of desirable features such as mild reaction conditions, cost efficiency and especially, spatiotemporal controllability. In particular, visible light induced polymerizations have been attracting considerable attention due to the concerns on cost efficiency, light penetration and environment safety. In this work, a crosslinked conjugated polymer, TT-BP, was designed and synthesized by Pd (0) catalyzed Suzuki coupling reaction. It was used as a photocatalyst for visible light induced free radical and cationic polymerizations in the presence of diphenyliodonium salt. The reactions were performed for 8 and 24 h in high yields, for which the photocatalyst TT-PB was used repeatedly for each reaction. The maximum conversion reached to 76 % in free radical polymerization of MMA, while the maximum conversion was obtained in cationic polymerization of IBVE with 82 %. This report on reusable conjugated polymer that have been used as a photocatalyst during free-radical and cationic photopolymerizations may lead to the emergence of a new perspective for photocatalyst and photopolymerization processes.

Organic field-effect transistors based on two-dimensional molecular crystals of thiophene/selenophene-based triacene asymmetric derivatives as active layer

From 2,5-di(trimethylsilanyl)dithieno[2,3-b:3′,2′-d]thiophene ((TMS)2-DTT) and (TMS)2-diseleno[2,3-b:3′,2′-d]thiophene ((TMS)2-DST), asymmetric organic semiconductor materials (E)− 2-(4-octylstyryl)− 5-phenyl-DTT (PEP-DTT) and (E)− 2-(4-octylstyryl)− 5-phenyl-DST (PEP-DST) were synthesized via bromination, Suzuki coupling, deprotection, formylation and Wittig reactions, with the yields of 48% and 28%, respectively. Apart from the synthetic work, two-dimensional molecular crystals (2DMCs) with a growth size of few hundreds of micrometers of PEP-DTT and PEP-DST were successfully realized for organic field-effect transistors (OFETs) devices through “layer-defining strategy”. Bottom-gate/top-contact OFETs on the basis of PEP-DTT and PEP-DST 2DMCs as active layers displayed p-channel features with maximum mobility of 2.04 and 1.36 cm2 V−1 s−1, respectively.

Synthesis of Trifluoromethylated Pyrimido[1,2-b]indazole Derivatives through the Cyclocondensation of 3-Aminoindazoles with Ketoester and Their Functionalization via Suzuki-Miyaura Cross-Coupling and SNAr Reactions.

A new series of trifluoromethylated pyrimido[1,2-b]indazol-4(1H)-one derivatives was synthesized with good to excellent yields through a simple condensation of 3-aminoindazole derivatives with ethyl 4,4,4-trifluoro 3-oxobutanoate. The functionalization of the corresponding chlorinated fused tricyclic scaffolds via Suzuki-Miyaura and aromatic nucleophilic substitution reactions led to the synthesis of highly diverse trifluoromethylated pyrimido[1,2-b]indazole derivatives with good yields.

Synthesis of Chiral Biphenyl Monophosphines as Ligands in Enantioselective Suzuki-Miyaura Coupling.

Herein, we describe our design and synthesis of novel chiral monophosphine ligands by the short-step addition of chiral lactates as side chains to the well-known ligand SPhos/RuPhos. The new chiral ligands were shown to be highly efficient in palladium-catalyzed Suzuki-Miyaura coupling, providing a series of axially chiral biphenyl products in high yield and high enantioselectivity. Furthermore, the gram-scale reaction and the diverse conversions of the products demonstrated the potential utility of the approach.

Synthesis of biphenyl via sustainable Suzuki-Miyaura coupling reaction using mesoporous MCF-supported tin-palladium nanoparticles

The current work presents a novel approach to synthesizing monometallic palladium (Pd) and bimetallic tin-palladium (Sn-Pd) nanoparticles anchored to mesostructured cellular foam silica (MCF). The monometallic catalyst Pd@MCF was prepared by the impregnation method, whereas the bimetallic catalyst Pd@MCF(Sn) was prepared by a green electroless reduction method. Our findings demonstrate that the bimetallic Sn-Pd nanoparticles produced through green electroless reduction exhibit no aggregation or clustering, and possess high and uniform dispersion, smaller average particle size and a narrower distribution of particle size than Pd nanoparticles obtained via impregnation. The synthesis of Pd@MCF(Sn) used tin as one of the metallic components of the catalyst and also as a reducing agent rather than conventionally used harmful reducing agents in the electroless reduction method. Remarkably, the introduction of tin into the catalyst system also displays a synergistic effect in the Suzuki-Miyaura coupling (SMC) reaction. The monometallic Pd@MCF catalyst was outperformed by the bimetallic Pd@MCF(Sn) catalyst in terms of catalytic activity for SMC reaction of phenylboronic acid with iodobenzene to produce biphenyl without using toxic reagents, organic solvents, costly phosphine ligands or protective atmospheres. This study also explored and optimized the factors controlling the reaction rate, offering insightful information to improve the production of biphenyl. The reaction follows a second-order kinetics with an apparent activation energy of 8.2 Kcal/mol by applying the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism. Here, we present a promising strategy for formulating a highly effective and eco-friendly catalyst for sustainable production of biphenyl using Suzuki-Miyaura coupling reaction.

Synthesis and Fluorescent Properties of Some Benzothiazole Derivatives Synthesized via Suzuki Cross Coupling Reaction

Synthesis and Fluorescent Properties of Some Benzothiazole Derivatives Synthesized via Suzuki Cross Coupling Reaction

Decoration of MnFe2O4@cys with Pd as a highly efficient nanocatalyst in C-C coupling reaction at ambient temperature

An environmentally friendly nano-catalyst was prepared by the functionalization of MnFe2O4 with cysteine (MnFe2O4@cys) and decoration with Pd(0) (MnFe2O4@cys/Pd) and fully characterized with physicochemical techniques. As-prepared MnFe2O4@cys/Pd was applied as a catalyst in the carbon-carbon (C-C) Suzuki-Miyaura coupling reaction using various aryl halides and phenylboronic acid with electron withdrawing and electron donating groups. The MnFe2O4@cys/Pd catalyst showed high efficiency, achieving significant reaction conversions and yields even with small amounts used in mild conditions such as room temperature and green solvents. The new nanocatalyst was stable, easily isolated by an external magnet, and was used at least 5 times without any noticeable decrease in its catalytic efficiency.

Zwitterionic Aqua Palladacycles with Noncovalent Interactions for meta-Selective Suzuki Coupling of 3,4-Dichlorophenol and 3,4-Dichlorobenzyl Alcohol in Water.

The site-selective reaction of substrates with multiple reactive sites has been a focus of the current synthetic chemistry. The use of attractive noncovalent interactions between the catalyst and substrate is emerging as a versatile approach to address site-selectivity challenges. Herein, we designed and synthesized a series of palladacycles, to control meta-selective Suzuki coupling of 3,4-dichlorophenol and 3,4-dichlorobenzyl alcohol. Noncovalent interactions directed zwitterionic aqua palladacycles catalyzed meta-selective Suzuki couplings of 3,4-dichloroarenes bearing hydroxyl in water have been developed. Experiments and density functional theory (DFT) calculations demonstrated that the electrostatic interactions play a critical role in meta-selective coupling of 3,4-dichlorophenol, while meta-selective coupling of 3,4-dichlorobenzyl alcohol arises due to the hydrogen-bonding interactions.

Unveiling the potential of Pd(II)‐covalent organic polyimide framework in Suzuki coupling reactions: A study on synthesis, characterization, and catalytic efficiency

In this research, a highly effective heterogeneous Pd catalytic system was conceived by immobilizing Pd(II) onto a substrate composed of covalent organic polyimide frameworks (PI‐COF). The synthesized catalyst underwent comprehensive characterization using techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption analysis (Brunauer–Emmett–Teller [BET]), Fourier transform infrared (FT‐IR), thermogravimetric analysis (TGA), and inductively coupled plasma atomic emission spectroscopy (ICP‐AES). Subsequently, the catalytic activity of this immobilized Pd catalyst was explored in the context of the Suzuki reaction. The reactions at 70°C up to 1 h under a normal atmosphere in water result in biaryls at good to excellent yields (>90%). More importantly, the leaching of Pd(II) during the reaction process could be negligible (about 0.5 ppm), which is crucially important when preparing bioactive species. The loading of Pd(II) ions on the PI‐COF was 0.49 mmol/g. The catalyst exhibited exceptional performance, demonstrating remarkable efficacy in catalyzing a wide range of aryl halides (excluding aryl chlorides) when reacted with phenylboronic acid under environmentally friendly reaction conditions. Notably, the catalyst exhibited robust recyclability, retaining its catalytic activity throughout 5 reaction cycles without any significant decrease.

Bimetallic Cu/Pd(ppm)-catalyzed Suzuki-Miyaura couplings: DFT studies on mechanism, roles of Pd(ppm) and ligands

Transition metal-catalyzed Suzuki-Miyaura coupling (SMC) reaction is an important method to constructe the C-C bond. In this work, the mechanisms of SMC between ArI and ArB(OH)2 (Ar=C6H4(OCH3)) catalyzed by single [Cu] catalyst and bimetallic [Cu]/[Pd] catalysts have been studied by DFT calculations. Comparing to the N, O-bidentate ligand, the N, P-bidentate ligand coordinated [L12-Cu] catalyst is not efficient for the above reaction, due to the high energy barrier of the C-C coupling procedure. The different coordination mode of the N, O-bidentate ligand increases the positive charge of coupling C atom, lowering the energy barrier when catalyzed by [L13-Cu]. The [Cu]/[Pd] catalyzed process involves two cycles: LCuAr is obtained from the [Cu] catalyzed cycle by the reaction between ArB(OH)2 and [L12Cu]. The [Pd] catalyzed cycle consists of four steps: L12Pd(0) insertion into C-I bond by oxidation addition, coordination transformation, transmetallation between LCuAr and ArPdI, and C-C coupling by reductive elimination. In these two cycles, the coordination transformation of the Pd is the rate-determining step. The participation of [Pd] catalyst changes the C-C coupling process from the Cu center to the Pd center, which lowers the energy barrier and makes the reaction become easier.

I2/CAN as a Mild and Efficient Reagent for Oxidative Csp3‐Csp2 Cleavage of 3,3′‐Bis‐7‐azaindolylmethane: A Rapid One‐Pot Access to 3‐Formyl and 3‐Iodo‐7‐azaindoles

AbstractThe combination of I2/CAN has emerged as a mild and powerful reagent for the oxidative Csp3‐Csp2 cleavage of 3,3′‐bis‐7‐azaindolylmethane to provide a quantitative combined yield of 3‐formyl and 3‐iodo‐7‐azaindole in a one‐pot reaction at RT. A plausible mechanism and characterization, including XRD, has been described. The synthetic transformations of title compounds were explored by reduction, Click, reductive amination, and Suzuki coupling reaction.

Synthesis of Unsymmetrically Substituted [5]Helicenes by Tandem Arylation of Binaphthyl by Suzuki Coupling and C−H Activation

AbstractWe report a step‐efficient approach for the synthesis of unsymmetrically substituted naphtho[1,2‐g]chrysenes by tandem arylation of 2,2’‐diiodo‐1,1’‐binaphthyl with arylboronic acids, which proceeds through Suzuki coupling followed by intramolecular arylation by C−H activation. Substrate screening examining over 30 meta‐ and/or para‐substituted arylboronic acids showed that this approach provides the desired helicene products most effectively if arylboronic acids have a small acidifying group at the meta‐position. In the case of unsymmetrically substituted arylboronic acids, the regioselectivity of C−H activation is directed by the attached group(s), its effect on the C−H acidity of the adjacent position, its coordination ability, as well as steric hindrance. Interestingly, selected [5]helicenes exhibited attractive deep blue emission with fluorescence lifetimes slightly exceeding 10 ns.

Impact of the position of nitrogen atom on the liquid crystal, optical and multi-stimuli response behaviors of rod-like mesogens containing multiple functional building blocks

Two novel rod-like mesogens containing one cyanostyrene, one pyridine and one pyrene as π-conjugate rigid core were designed and synthesized by Suzuki coupling and Knoevenagel reactions. The effect of the position of nitrogen-atom on the thermodynamic behavior, liquid crystalline self-assembly, optical behavior, mechanochromism behavior and acidochromism behavior was investigated. The rod-like mesogen in which the nitrogen atom is adjacent to the pyrene displays a phase transition from smectic A to smectic C by increasing temperature, whereas the other rod-like mesogen can only self-assemble into smectic C phase. This difference in mesophase transition behavior might be attributed to the position of nitrogen-atom which induces the change in molecular configuration. Both mesogens exhibit positive solvatochromism and high fluorescence in both solution state and aggregated state which might be attributed to the intramolecular charge transfer and twisted molecular configurations, respectively. Reversible mechanochromism behavior due to changes in molecular stacking and acidochromism behavior due to protonation and deprotonation were also achieved. These multi-stimuli responsive behaviors of the designed rod-like mesogens demonstrate potential applications in the field of multifunctional materials.

Rosa Indica flower petal anthocyanin mediated biogenic synthesis of PdNPs: Catalyst intended for the Suzuki-Miyaura reactions

In the present work, theRosa Indicaflowerpetals anthocyanin extract has been employed as a “green” natural source for the synthesis and topping of noble metal nanoparticles [palladium nanoparticles (PdNPs)]. TheRosa Indicaflowerpetals anthocyanin extract effectively replaces the toxic chemicals and stabilizers. The formed PdNPs were exposed to their structural properties examination by the Ultraviolet–Visible absorption, Energy-dispersive X- ray and Fourier TransformInfrared spectroscopic analysis. The diffractionpattern of the PdNPs@ rose-anthocyanin to the X-ray recognizes their crystalline nature. In addition, the detailed analysis of the X-ray pattern and microscopic images ofFESEM, TEM reveals that formed PdNP@ rose-anthocyanin possesses FCC crystal lattice with average dimensions of the particle ∼ 12 nm. The EDS analysis shows that the PdNPs@ rose-anthocyanin contains ∼ 80 wt% PdNPs. Further, the PdNP@ rose-anthocyanin were efficiently catalyses the Suzuki-Miyaura cross-coupling (CC) reactions between an aryl halide and phenylboronic acid in the presence of K2CO3 as a suitable base. To catalyse the reaction, PdNPs@ rose-anthocyanin works as heterogeneous catalyst in the absence of heating. Moreover, it provides a good to high yield of the corresponding coupled products under aerobic conditions with optimum reaction time in the aqueous medium, particularly at room temperature with a virtuous Turnover number relative to several synthesized PdNPs. Further, the catalyst PdNP@ rose-anthocyanin shows righteous catalytic activity without significant loss in its efficiency up to four reusable cycles.

Total synthesis of 1,2,11,12E-tetradehydrohardwickiic acid

Clerodane diterpenoids are a large class of natural products found in various species and exhibit a wide range of biological activities. trans-Clerodanes, which feature a trans-decalin core structure, are the most common subfamily of clerodane diterpenoids. Previously, we have developed a tail-to-head cyclization strategy via a titanium(III) catalyzed alkyne terminated radical polyene cyclization to synthesis C18 non-oxidized trans-clerodanes and sesquiterpene (hydro)quinones with a similar trans-decalin skeleton. In this communication, we reported the first asymmetric total synthesis of 1,2,11,12E-tetradehydrohardwickiic acid, a C18 oxidized trans-clerodane, through the product of titanium(III) catalyzed tail-to-head polyene cyclization of the derivative of farnesol. A hydroxyl group directed hydrogenation of alkene, an E-selective hydrobromination of terminal alkyne, and a Suzuki coupling were the key steps of the synthesis.

Palladium-Catalyzed Cross-Coupling of gem-Difluorocyclopropanes with gem-Diborylalkanes for the Synthesis of Boryl-Substituted Fluorinated Alkenes.

This study presents a novel method for the regioselective coupling of gem-difluorinated cyclopropanes with gem-diborylmethane, utilizing a Pd-catalyst system. This innovative approach enables the synthesis of 2-fluoroalkenyl monoboronate scaffolds with high Z-selectivity. The resulting products undergo further transformations, including oxidation, Suzuki cross-coupling, and trifluoroborylation, all of which are achieved with good yields. This work introduces a valuable synthetic pathway to access important fluorinated compounds for various applications in organic chemistry.

Decarboxylative Iodination and Suzuki-Miyaura Coupling Reactions to Access Chiral 3,3'-Diaryl-1,1'-bi-2-naphthols.

An efficient synthesis of the enantiomerically pure 3,3'-bis-arylated BINOLs is accomplished through decarboxylative iodination of the dimethyl ether derivative of BINOL-3,3'-dicarboxylic acid followed by Suzuki-Miyaura coupling using a one-pot protocol. The decarboxylative iodination is effected with the dimethyl ether derivative of BINOL-3,3'-dicarboxylic acid using iodine as a terminal oxidant and the cheaply available K3PO4 as a base under neat conditions. This protocol facilitated the introduction of the aryl group at the 3,3'-position on the binaphthyl system using aryl boronic acid through a palladium-catalyzed Suzuki-Miyaura coupling reaction.

Surface-Modified Pd/CeO2 Single-Atom Catalyst Shows Increased Activity for Suzuki Cross-Coupling.

Single-atom catalysts (SACs) comprise catalytically active atoms dispersed on supports; they combine the high activity and site uniformity of homogeneous catalysts with the ease of separability of heterogeneous catalysts. However, SACs lack fine control over the active site, provided by ligands in homogeneous catalysts. In this work, we demonstrate that modification of the support with an organic monolayer is a viable approach to improving the catalytic performance. The addition of catechol-type monolayers to a Pd/CeO2 SAC increases its catalytic activity for Suzuki cross-coupling, a central reaction in the synthesis of fine chemicals and pharmaceuticals. Kinetic trials reveal that the coating reduces the activation energy from 49 ± 9 to 22 ± 5 kJ/mol and produces a 4-fold rate enhancement at 25 °C, an effect we attribute to π-π interactions between the reactant and the catechol coating. Further development of this approach could vastly increase the utility of SACs in organic synthesis.

Aerobic bacteria-supported biohybrid palladium catalysts for efficient cross-coupling reactions

Palladium-based catalysts are of key importance in organic synthesis due to their versatility and tolerance for a wide range of functional groups. However, their use challenged by increasing sustainability issues and complex preparation methods. Consequently, the development of new heterogeneous catalysts with enhanced sustainability is of significant interest. Typically, the synthesis of carbon supports for palladium is associated with high energy consumption or the generation of substantial chemical waste, prompting extensive research into the creation of sustainable biological supports. In this study, the potential use of aerobic bacterial cells as a support for palladium nanoparticles was explored, using Paracoccus yeei VKM B-3302 as a model organism. Electron microscopy, powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of palladium particles on the cell surface as well as inside microorganisms following deposition from a solution. Control experiments established that bacterial cells do not interact with either the reactants or the products of selected cross-coupling processes. Furthermore, bacteria do not affect the analysis of reaction mixtures by nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC–MS). At the same time, palladium/Paracoccus yeei demonstrated efficient catalysis of the Mizoroki-Heck and Suzuki-Miyaura reactions, yielding results comparable to commercial palladium on carbon (Pd/C) catalysts. Employing a fresh start procedure and catalyst separation method, the catalyst was successfully recycled and reused across five cycles, maintaining good catalytic activity. In a broader aspect, bacteria-supported biohybrid palladium catalysts can represent a new type of catalysts worth to explore in a number of processes, where sustainability issues are concerned.

Fluorene and Tetraphenylsilane Based Conjugated Microporous Polymer Nanoparticles for Highly Efficient Nitroaromatics Detection in Aqueous Media

AbstractConjugated microporous polymers (CMPs) are considered promising sensing materials for the detection of nitroaromatics. Unfortunately, the photoluminescence (PL) sensing application in water media is limited, owing to the poor solubility/dispersion in aqueous media. Here, two novel CMPs named poly(dimethylfluorene‐co‐tetrakis(4‐phenyl)silane)s (P4SiF) and poly(dimethylfluorene‐co‐tetrakis(3‐phenyl)silane)s (P3SiF) nanoparticles based on fluorene group and tetraphenylsilane unit are prepared using Suzuki coupling in water/toluene miniemulsion. P4SiF and P3SiF possess spherical particle morphology with sizes of 45 and 60 nm, respectively, and porous structure with pore diameters of both 1.9 nm. PL sensing experiments based on P4SiF and P3SiF nanoparticles in aqueous media show a sensitive and selective detection toward 2,4,6‐trinitrophenol (TNP). It is worth noting that the PL quenching effect toward TNP is not significantly changed after the addition of other nitro compounds, proving the excellent anti‐interference characteristic and highly selective detection of the polymers in water. Moreover, the t‐test indicates that the PL sensing method using P4SiF and P3SiF nanoparticles as sensing materials realizes the reliable detection of TNP in actual water samples at a 95% confidence level. Finally, the PL sensing mechanism is investigated, showing that the inner filter effect is the main factor in the PL quenching process of TNP in aqueous media.