Cyanation Of Aryl Halides Research Articles

Synthesis and characterization of a green and recyclable arginine-based palladium/CoFe2O4 nanomagnetic catalyst for efficient cyanation of aryl halides.

The utilization of magnetic nanoparticles in the fields of science and technology has gained considerable popularity. Among their various applications, magnetic nanoparticles have been predominantly employed in catalytic processes due to their easy accessibility, recoverability, effective surface properties, thermal stability, and low cost. In this particular study, cyanuric chloride and arginine were utilized to synthesize an arginine-based oligomeric compound (ACT), which was supported on cobalt ferrite, resulting in a green catalyst with high activity and convenient recyclability for the cyanation reaction of aryl halides. The Pd/CoFe2O4@ACT nanomagnetic catalyst demonstrated excellent performance in the cyanation of various aryl iodides and bromides, yielding favorable reaction outcomes at a temperature of 90 °C within a duration of 3 hours. The synthesized nanoparticles were successfully characterized using various techniques, including FTIR, FE-SEM, EDX/MAP, XRD, TEM, TGA, BET, and ICP-OES. Moreover, the Pd/CoFe2O4@ACT catalyst exhibited remarkable catalytic activity, maintaining an 88% performance even after five consecutive runs. Analysis of the reused catalyst through SEM and TEM imaging confirmed that there were no significant changes in the morphology or dispersion of the particles. Ultimately, it was demonstrated that the Pd/CoFe2O4@ACT nanomagnetic catalyst outperformed numerous catalysts previously reported in the literature for the cyanation of aryl halides.

Triple Action of an Attractive Deep Eutectic Solvent in the Synthesis of Aryl Nitriles and Substituted Triazoles Using a Magnetically Reusable Fe3O4@SiO2@PrNCu Catalyst

AbstractHeterogeneous Cu‐catalyzed cyanation of aryl halides and Click cycloaddition of alkyl halides, sodium azide, and terminal alkynes were optimized to be cost effective and environmentally benign. A green Deep Eutectic Solvent (DES) and Fe3O4@SiO2@PrNCu magnetic catalyst was used. This new DES was designed to acts as both base and reaction promoter, beside its major role as solvent, in the studied Cu‐catalyzed reactions. Additionally, hydrophobic/hydrophilic balance of employed DES, enables easier association of polar or nonpolar reactants in the course of the reactions compared to conventional green but only polar solvent such as water. Therefore, this DES provides better diffusion onto the catalyst‘s surfaces and thus accelerates the catalytic process. Simple experimental procedures with purposeful design and use toward DES accompanied by utilization of green and reusable catalyst could be considered as alternative features in this new protocol compared to existing methods for Cu‐catalyzed reactions.

Open-Source Chromatographic Data Analysis for Reaction Optimization and Screening.

Automation and digitalization solutions in the field of small molecule synthesis face new challenges for chemical reaction analysis, especially in the field of high-performance liquid chromatography (HPLC). Chromatographic data remains locked in vendors' hardware and software components, limiting their potential in automated workflows and data science applications. In this work, we present an open-source Python project called MOCCA for the analysis of HPLC-DAD (photodiode array detector) raw data. MOCCA provides a comprehensive set of data analysis features, including an automated peak deconvolution routine of known signals, even if overlapped with signals of unexpected impurities or side products. We highlight the broad applicability of MOCCA in four studies: (i) a simulation study to validate MOCCA's data analysis features; (ii) a reaction kinetics study on a Knoevenagel condensation reaction demonstrating MOCCA's peak deconvolution feature; (iii) a closed-loop optimization study for the alkylation of 2-pyridone without human control during data analysis; (iv) a well plate screening of categorical reaction parameters for a novel palladium-catalyzed cyanation of aryl halides employing O-protected cyanohydrins. By publishing MOCCA as a Python package with this work, we envision an open-source community project for chromatographic data analysis with the potential of further advancing its scope and capabilities.

Magnetically separable triazine-based Cu(ii)-vitamin B5 complex in nitromethane toward efficient heterogeneous cyanation reaction of aryl halides.

In the current study, a highly efficient heterogeneous copper catalyst has been developed by supporting copper acetate on a magnetically separable triazine-vitamin B5 system. After the successful characterization of the prepared nanoparticles by various techniques such as FT-IR, FE-SEM, EDX/MAP, XRD, TEM, TGA, VSM, and ICP-OES, the catalytic efficiency of them were evaluated in the cyanation reaction of aryl halides in the presence of nitromethane as a non-toxic and cost-effective cyanation source. The cyanation products were obtained in desirable yields. Notably, the magnetic nanocatalyst can be easily recovered and reused at least five times without a significant decrease in its performance.

In-situ formation of Ag NPs on the ribonic γ-lactone-modified UiO-66-NH2: An effective catalyst for organic synthesis and antibacterial applications

Using of eco-friendly, cost-effective, and durable compounds as reducing and stabilizing reagents for metallic nanoparticles (MNPs) has always been alluring for the preparation of nanocatalysts. Herein, a porous heterogeneous catalyst was prepared via green deposition of Ag NPs on the surface of functionalized metal-organic framework (MOF), Zr-UiO-66-NH2. Initially, UiO-66-NH2 was modified with D-(+)-ribonic γ-lactone (RL), as a class of carbohydrates (CHs), which provides plenty of hydroxyl groups on the surface for reducing Ag+ ions and stabilizing Ag NPs. The catalytic activity of UiO-66-NH-RL-Ag was tested for the reduction of 4-nitrophenol in the presence of NaBH4 and the cyanation of aryl halides, for the first time, in the presence of nontoxic cyanating source K4[Fe(CN)6]·3 H2O. The nanocatalyst effectively reduced 4-nitrophenol with a turnover frequency (TOF) of 333.2 h–1. The kinetic studies illustrated that the reaction follows a pseudo-first-order kinetic. Moreover, UiO-66-NH-RL-Ag exhibited good catalytic activity with high efficiencies in the synthesis of various aryl nitriles. Furthermore, UiO-66-NH-RL-Ag showed a prominent antibacterial activity and inhibited the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Ni-Catalyzed Cyanation of Aryl Halides Using 1,4-Dicyanobenzene as an Easily Accessible Cyanide Source

Ni-Catalyzed Cyanation of Aryl Halides Using 1,4-Dicyanobenzene as an Easily Accessible Cyanide Source

DFT studies on the mechanisms of nickel-catalyzed reductive-coupling cyanation of aryl bromide

The mechanisms of nickel-catalyzed cyanation of aryl halides with 2-methyl-2-phenylmalononitrile (MPMN) through the reductive-coupling reactions have been investigated using density functional theory (DFT) calculations. The NiI catalytic cycle was more favored over the Ni° catalytic cycle. The results showed that the overall catalytic cycle included the oxidative addition, reduction, 1,2-migratory insertion, β-C elimination, product separation and catalyst regeneration steps. We calculated the high spin state of triplet Ni catalytic cycle and the low spin state of singlet Ni catalytic cycle. The results showed that the rate-determining step in the whole catalytic cycle was the oxidative addition step where the Gibbs free energy barrier ΔGsol in N,N-dimethylacetamide (DMA) solution is 14.8 kcal/mol, which kept consistent with the experimental results.

Hyperbranched polymer immobilized palladium nanoparticles as an efficient and reusable catalyst for cyanation of aryl halides and reduction of nitroarenes

A new nitrogen-rich hyperbranched polymer comprising imidazolium and triazole moieties used for stabilization of Pd nanoparticles. The resulting new material, PolyTZ-IL@Pd NPs, was characterized with different techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-Ray (EDX), and transmission electron microscopy (TEM) analysis. PolyTZ-IL@Pd NPs has been used as an efficient catalyst in the reduction of nitroarenes to amines and cyanation of aryl bromides and iodides. The catalyst showed high stability and recyclability and recycled at least 10 times in reduction of 1‑chloro-4-nitrobenzene and 5 times in cyanation of iodobenzene.

Palladium (II) Complex Supported on Magnetic Nanoparticles Modified with Phenanthroline: A Highly Active Reusable Nanocatalyst for the Synthesis of Benzoxazoles, Benzothiazoles and Cyanation of Aryl Halides

Palladium (II) Complex Supported on Magnetic Nanoparticles Modified with Phenanthroline: A Highly Active Reusable Nanocatalyst for the Synthesis of Benzoxazoles, Benzothiazoles and Cyanation of Aryl Halides

Photochemically Enabled, Ni-Catalyzed Cyanation of Aryl Halides.

A light-promoted Ni-catalyzed cyanation of aryl halides employing 1,4-dicyanobenzene as a cyanating agent is reported. A broad array of aryl bromides, chlorides, and druglike molecules could be converted into their corresponding nitriles (65 examples). Mechanistic studies suggest that upon irradiation, the oxidative addition product Ni(II)(dtbbpy)(p-C6H4CN)(CN) undergoes homolytic cleavage of the Ni-aryl bond to generate an aryl radical and a Ni(I)-CN species, the latter of which initiates subsequent cyanation reactions.

Hyperbranched Polymer Immobilized Palladium Nanoparticles as an Efficient and Reusable Catalyst for Cyanation of Aryl Halides and Reduction of Nitroarenes

Hyperbranched Polymer Immobilized Palladium Nanoparticles as an Efficient and Reusable Catalyst for Cyanation of Aryl Halides and Reduction of Nitroarenes

Photoredox Catalysis Unlocks the Nickel-Catalyzed Cyanation of Aryl Halides under Benign Conditions

The transition-metal-catalyzed cyanations of aryl halides are among the most used methods for synthesizing aryl nitriles. Despite tremendous advances, cyanating an aryl halide in a facile and benig...

Ni-catalyzed enantioselective [2 + 2 + 2] cycloaddition of malononitriles with alkynes

Summary Efficient strategies to assemble enantioenriched pyridine derivatives are highly important, given their significance in both synthetic and medicinal chemistry. Here, we report an enantioselective nickel-catalyzed intermolecular [2 + 2 + 2] cycloaddition of alkyne-tethered malononitriles with alkynes for the synthesis of densely substituted pyridines. The α-all-carbon quaternary center adjacent to pyridine is introduced by desymmetrizing the two cyano groups of disubstituted malononitriles. Notably, terminal alkynes are also tolerated with good regioselectivity to afford tetrasubstituted pyridines. Zinc halide is essential to enable the occurrence of the transformation by promoting the hetero-cyclometallation step. The reaction uses bio-renewable 2-MeTHF as the solvent and features mild reaction conditions, good functional group compatibilities, and enantioselectivities. This study offers a straightforward approach to the valuable enantioenriched heteroarenes from feedstock chemicals by forming three bonds and one quaternary stereocenter simultaneously in a single reaction step.

Decorated palladium nanoparticles on chitosan/δ-FeOOH microspheres: A highly active and recyclable catalyst for Suzuki coupling reaction and cyanation of aryl halides

In this study, an eco-friendly and low cost magnetic nanocomposite consisting of chitosan/δ-FeOOH microspheres (CS/δ-FeOOH) was fabricated as a stabilizer by using a simple method. Pd nanoparticles (Pd NPs) were decorated on the designed CS/δ-FeOOH, and the resulting Pd NPs@CS/δ-FeOOH microspheres were employed as a heterogeneous catalyst in the construction of biaryl and benzonitriles. Pd NPs@CS/δ-FeOOH microspheres efficiently catalyzed the conversion of aryl iodides and bromides to the desired biaryls within 3 h. Moreover, Pd NPs@CS/δ-FeOOH microspheres showed high catalytic potential against synthesis of benzonitriles by providing yields up to of 99% within 4 h. More importantly, it was proved that Pd NPs@CS/δ-FeOOH microspheres were able to be easily recycled and reused up to eight runs for both reactions. This study reveals that Pd NPs@CS/δ-FeOOH microspheres are useful and recyclable nanocatalysts, which catalyze the synthesis of biaryl and benzonitriles with good reaction yields.

Facile preparation of nanostructured Pd-Sch-δ-FeOOH particles: A highly effective and easily retrievable catalyst for aryl halide cyanation and p-nitrophenol reduction

Iron based compounds are good candidates as supports to immobilize different transition metals due to their eco-friendly nature, capability of facilitating chemical modifications, inexpensiveness, high stability and easy recoverability. In this study, palladium nanoparticles (Pd NPs) were successfully stabilized on designed Schiff base modified δ-FeOOH particles as a highly effective and readily recoverable heterogeneous catalyst (Pd-Sch-δ-FeOOH nanocatalyst). The catalyst was fabricated via a facile multi-step approach without utilizing any additional reducing agents. The Pd-Sch-δ-FeOOH was characterized by Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Characterization studies confirmed that the prepared small sized Pd NPs were spherically shaped and well dispersed on the surface of Schiff base modified δ-FeOOH. The catalytic efficiency of Pd-Sch-δ-FeOOH nanocatalyst was then tested in the preparation of benzonitriles through cyanation of aryl halides using K4[Fe(CN)6] has been utilized as a cyanation agent and also reduction of p-nitrophenol (p-NP) using NaBH4 as the reducing agent. Benzonitriles were characterized using GC-MS. Catalytic studies showed that benzonitriles were obtained in good reaction yields in the presence of heterogeneous Pd-Sch-δ-FeOOH nanocatalyst (87–98%). It was found that Pd-Sch-δ-FeOOH was also a useful nanocatalyst for p-NP reduction at ambient temperature in eco-friendly media within 2 min. The reduction rate for p-NP with Pd-Sch-δ-FeOOH was measured via UV–Vis spectroscopy from 250 nm to 550 nm. Furthermore, Pd-Sch-δ-FeOOH nanocatalyst was able to remain active for six successive runs due to its recyclable/reusable nature.

Revisiting the synthesis of aryl nitriles: a pivotal role of CAN.

Facilitated by the dual role of Ceric Ammonium Nitrate (CAN), herein we report a cost-effective approach for the cyanation of aryl iodides/bromides with CAN-DMF as an addition to the existing pool of combined cyanation sources. In addition to being an oxidant, CAN acts as a source of nitrogen in our protocol. The reaction is catalyzed by a readily available Cu(ii) salt and the ability of CAN to generate ammonia in the reaction medium is utilized to eliminate the additional requirement of a nitrogen source, ligand, additive or toxic reagents. The mechanistic study suggests an evolution of CN- leading to the synthesis of a variety of aryl nitriles in moderate to good yields. The proposed mechanism is supported by a series of control reactions and labeling experiments.

Pd/CoFe2O4/chitosan: A highly effective and easily recoverable hybrid nanocatalyst for synthesis of benzonitriles and reduction of 2-nitroaniline

In this study, a novel catalyst system with high activity and easy recoverability was successfully prepared through the deposition of Pd nanoparticles (NPs) onto designed sustainable hybrid beads containing magnetic cobalt ferrite and chitosan (Pd/CoFe2O4/chitosan). The catalytic potential of Pd/CoFe2O4/chitosan hybrid nanocatalyst was then assessed in i) preparation of benzonitriles via aryl halides cyanation and ii) reduction of 2-nitroaniline (2-NA). Various aryl iodides and bromides were successfully cyanated by Pd/CoFe2O4/chitosan hybrid nanocatalyst with excellent reaction yields within 3 h. In addition to the production of benzonitriles, the hybrid nanocatalyst showed excellent activity by reducing 2-NA in 65 s. It was proved that the Pd/CoFe2O4/chitosan hybrid nanocatalyst outperformed many catalysts used in the cyanation of aryl halides and catalytic reduction of 2-NA previously reported in the literature. Moreover, it was found that the designed Pd/CoFe2O4/chitosan hybrid nanocatalyst was easily and effectively separated from the reaction mixture using an external magnet and reused several times in catalytic reactions without considerable loss of catalytic activity.

Withdrawal: Photoredox Catalysis Unlocks the Nickel‐Catalyzed Cyanation of Aryl Halides under Benign Conditions

Withdrawal: Photoredox Catalysis Unlocks the Nickel‐Catalyzed Cyanation of Aryl Halides under Benign Conditions

Withdrawal: Photoredox Catalysis Unlocks the Nickel-Catalyzed Cyanation of Aryl Halides under Benign Conditions.

The transition-metal-catalyzed cyanations of aryl halides are among the most used methods for synthesizing aryl nitriles. Despite tremendous advances, cyanating an aryl halide in a facile and benign fashion has generally been unsuccessful. The challenge for this significant transformation is the strong affinity of cyanide for metal centers, which makes organometallic catalysis elusive by hampering oxidative addition and reductive elimination. Herein, we demonstrate for the first time that nickel-catalyzed cyanations of aryl halides are readily enabled by visible-light photoredox catalysis, in which Ni(II) species are transiently oxidized to Ni(III) species, thereby facilitating the subsequent cyanide transfer and reductive elimination. Using this dual catalysis strategy, we cyanated aryl and alkenyl halides at room temperature in a highly benign manner (30 examples, 53-93% yields) by avoiding the use of air-sensitive ligands, Ni(0) processors, and hypertoxic cyanation reagents, while also not generating excess metal waste. Computational studies were also used to help understand the present transformation.

Palladium nanoparticles anchored polydopamine-coated graphene oxide/Fe3O4 nanoparticles (GO/Fe3O4@PDA/Pd) as a novel recyclable heterogeneous catalyst in the facile cyanation of haloarenes using K4[Fe(CN)6] as cyanide source

Pd(0) nanoparticles stabilized over polydopamine (PDA) capped magnetic GO/Fe3O4 nanocomposites (GO/Fe3O4@PDA/Pd) have been synthesized in variable Pd load following a post grafting approach. Pd has been reduced in situ by the functionalized PDA avoiding the use of external harsh reductant. The structural properties of the synthesized materials were studied by different analytical techniques like Field Emission Scanning electron microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), High Resolution Transmission Electron Microscopy (HRTEM), Fourier Transformed Infrared (FT-IR) spectroscopy, Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), Thermo Gravimetric Analysis (TGA), Powder X-Ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The novel GO/Fe3O4@PDA/Pd(0) nanocomposite exhibited excellent performance as a reusable catalyst in the facile cyanation of aryl halides using K4[Fe(CN)6] as a low cost and safe cyanating agent. The aryl nitriles were obtained in good to excellent yields and the catalyst was recycled up to 13 times with minimal change in its catalytic activity.