Cyanation Reaction Research Articles

Synthesis of Unsymmetrical Diarylfumaronitriles via Tandem Michael Addition and Oxidation under K3Fe(CN)6/O2 System.

An efficient formal alkenyl C-H cyanation reaction has been developed for the general synthesis of unsymmetrical diarylfumaronitriles in good to excellent yields. The reaction was achieved through tandem Michael addition and an oxidative process. The merits of this transformation include the use of K3Fe(CN)6 as a safe and nontoxic cyanide source, without an external noble metal catalyst, oxygen-involved reactions, easily available raw materials, good functional group tolerance, high stereoselectivity, and potential further application of the products.

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions.

The cyanation reaction has achieved rapid progress in recent times. The ability to exhibit multiple oxidation states increased the demand of ruthenium in the field of catalysis. These cyanation reactions have wide application in pharmacological and biological fields. This review gives an overview of the ruthenium-catalyzed cyanation reactions covering literature up to 2021.

Nickel-catalyzed cyanation reaction of aryl/alkenyl halides with alkyl isocyanides.

We herein describe a nickel-catalyzed cyanation reaction of aryl/alkenyl halides with alkyl isocyanides. Both aryl/alkenyl iodines and bromides were found to be competent electrophiles that reacted with alkyl isocyanides, affording nitrile compounds in moderate to good yields. A range of functional groups including halogens as well as hydroxyl, formyl, and acetamino groups were fairly compatible with the nickel catalysis. This protocol featured broad functional group tolerance, simple reaction conditions, and gram-scale synthesis.

Design and construction of polyaromatic group containing Cd(ii)-based coordination polymers for solvent-free Strecker-type cyanation of acetals

Solvent-free Strecker-type cyanation reactions of different acetals, with trimethylsilyl cyanide (TMSCN), are achieved under heterogeneous conditions by using Cd(ii) coordination polymers as catalysts.

Binuclear copper iodine cluster-based coordination sheets as photocatalysts for decarboxylative cyanation.

We synthesized two new MOFs (Cu-Tpxa-1 and Cu-Tpxa-2) that were used as heterogeneous photocatalysts, combining photocatalysis and copper catalysis to achieve decarboxylative radical cyanation reactions. This new heterogeneous catalysis method optimized the redox properties and excited-state lifetimes, providing a new idea for exploring photocatalytic mechanisms.

Water-Dispersible Pd–N-Heterocyclic Carbene Complex Immobilized on Magnetic Nanoparticles as a New Heterogeneous Catalyst for Fluoride-Free Hiyama, Suzuki–Miyaura and Cyanation Reactions in Aqueous Media

Pd–N-heterocyclic carbine complex immobilized on magnetic nanoparticles is synthesized and characterized by different techniques such as FT-IR, XPS, TEM, EDX, FESEM, VSM, TGA, and ICP. The synthesized catalyst was used as a new water dispersible heterogeneous catalyst in the fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water. By this method, different types of biaryls and aryl nitriles were synthesized in good to high yields by the reaction of a variety of aryl iodides, bromides and chlorides with triethoxyphenylsilane, phenylboronic acid and K4[Fe(CN)6]·3H2O, respectively. The presence of sulfonates as hydrophilic groups on the surface of the catalyst confers a highly water dispersible, active and yet magnetically recoverable Pd catalyst. The possibility to perform the reaction in water as a green medium, ease of the catalyst recovery and reuse by magnetic separation, and the absence of any additives or co-solvents make this method as an eco-friendly and economical protocol for the synthesis of biaryl derivatives and aryl nitriles. A new water dispersible heterogeneous Pd–N-heterocyclic carbene for the efficient fluoride-free Hiyama, Suzuki–Miyaura and cyanation reactions in pure water is developed.

Construction of CF3-Functionalized Fully Substituted Benzonitriles through Rauhut-Currier Reaction Initiated [3 + 3] Benzannulation.

Though numerous cyanation reactions have been developed for the synthesis of benzonitriles, the construction of valuable fully substituted benzonitriles is still a challenging task. Herein, we reported a tertiary amine-catalyzed [3 + 3]-benzannulation for the green synthesis of CF3-functionalized fully substituted benzonitriles. This strategy features exclusive chemoselectivity, high atom-economy, and good step-economy with environment-friendly reagents and mild conditions. Unique triphenyl-substituted dicyanobenzoate products could be rapidly constructed using this method. The practicality and reliability of this reaction were proved by the successful scale-up synthesis. A mechanistic study indicates that the [3 + 3]-benzannulation was initiated by an intermolecular Rauhut-Currier reaction.

Surface engineered Iridium-based magnetic photocatalyst paving a path towards visible light driven C-H arylation and cyanation reaction

The report presents the fabrication and application of a highly versatile, magnetic and robust iridium based photoredox nanocatalyst. Herein, Ir(PPy)3 based photocatalyst sites have been chemically engineered over the magnetic nanoparticles to encompass the captivating features of homogeneous iridium photocatalyst with the magnetically recyclable core. A household photoreactor was designed and fabricated to achieve highly selective visible light driven oxidative C-H arylation and C-H cyanation under sustainable and ambient reaction conditions utilizing the Ir@PyBz@ASMNPs photoredox nanocatalyst. The environment friendly Ir@PyBz@ASMNPs shows excellent photocatalytic activity, broad substrate adaptability and outstanding recyclability compared to the analogous homogeneous catalysts. Indeed, the Ir@PyBz@ASMNPs possess some key features including high surface area, high iridium metal loading and excellent stability. This work is expected to enlighten and provide new insights in the rational design of high performance and recoverable photoredox nanocatalyst through surface engineering strategy.

Copper Mediated Chemo‐ and Stereoselective Cyanation Reactions

AbstractEarth‐abundant transition metal based catalytic materials can become pivotal for clean chemical manufacturing due to their facile handling and air moisture stability replacing conventional expensive noble metal based catalytic systems. Amongst the non‐noble metals, copper based catalytic systems due to the variable oxidation states have been effectively used as the tunable and multifunctional catalytic materials for the promotion of selective organic transformations. These copper based catalytic systems effectively promote multifarious organic transformations promoting functionalization of the easily available organic substrates. Nitriles are a significant class of nitrogen‐containing compounds finding applications in pharmaceutical and fine chemical industries. Several organic and inorganic cyanide sources have been effectively usedto cyanate organic compounds by using multi‐ferrous copper catalysts. Furthermore, nitrile compounds are key components used for the synthesis of drug molecules and fabrication of functionalized materials.

An overview of microwave assisted cyanation reactions

AbstractCyano compounds are versatile intermediates in organic synthesis and have immense applications in diverse sectors including pharmaceuticals, industries, and agrochemicals. Microwave heating has enlightened synthetic chemistry due to its eco‐friendly nature ever since the first report. High product yield, shorter reaction time, less byproduct formation, selectivity, reproducibility and high product purity made this heating technique more acceptable. This review focuses on the diverse aspects of microwave assisted cyanation reactions. This is the first review on this topic and covers literature from 2000 to 2020.

Electron Donor‐Acceptor Complex Enabled Photocyanation of Tertiary Amines with a Stable and User‐Friendly Cyanobenziodoxolone Reagent

AbstractA visible light‐induced photocyanation of tertiary amines by a stable, less‐toxic and user‐friendly CN reagent cyanobenziodoxolone (CBX) was developed. This cyanation process does not require any photocatalyst, oxidant, base or additives, representing a set of extremely mild and succinct reaction conditions and a broad substrate scope. In addition to the frequently used N‐aryl amine derivatives, more challenging tertiary aliphatic amines (modified by a α‐silyl substituent) can also be photocyanated smoothly. Mechanistic studies reveal that the cyanation reaction is enabled by an electron donor–acceptor (EDA) complex formed by the interaction between the amine and the cyanobenziodoxolone reagent.

Mesoporous chromium oxide doped palladium catalysis for cyanation reaction of some aryl halides

A Pd/Cr2O3 hybrid catalyst for cyanation reaction of some aryl halides was synthesized and characterized by XRD, SEM/EDS and TEM. The porous structure of the catalyst was also investigated by BET analysis. All XRD characteristic lines were obtained for Cr2O3 and Pd/Cr2O3 hybrid in good agreement with the reference XRD data. It was found that average particle size of Pd/Cr2O3 composite was about 22 nm. The catalytic efficiency of the Pd/Cr2O3–catalyzed cyanation reaction was evaluated for some m- and p-substituted aryl halides. The influence of solvent, reaction time, and base on the activity of the Pd/Cr2O3 catalyst was investigated, and the optimal reaction conditions were systematically obtained. Catalytic investigations showed that Pd/Cr2O3 hybrid can exhibit very good catalytic performance for cyanation reaction of aryl halides with a high yield of around 90%, and retained its catalytic activity throughout successive 5 cycles. Comparative TEM images of Pd/Cr2O3 hybrid catalyst, as-synthesized and after 5th cycle, showed that nano-sized structure of Pd/Cr2O3 catalyst was protected without significant change.

Recent advances in the rhodium‐catalyzed cyanation reactions

AbstractCyanation reactions have found a dominant position in organic synthesis due to the propensity of the cyanide group for conversion to various other functionalities. This property has opened up wide application for cyanide group. In recent years, transition metal‐catalyzed reactions in general and rhodium‐catalyzed reactions in particular have attracted the attention of organic chemists, which lead up to a number of cyanation procedures and synthetic transformation of the cyanide group into highly functionalized products. This review provides an overview of the rhodium‐catalyzed cyanation reactions and subsequent transformations leading to the formation of various types of compounds such as amines, acids, indoles, isocyanides, nitriles, and oximes.

An advancement in the synthesis of nano Pd@magnetic amine-Functionalized UiO-66-NH2 catalyst for cyanation and O-arylation reactions

The magnetic MOF-based catalytic system has been reported here to be an efficient catalyst for synthesis of benzonitriles and diarylethers of aryl halides under optimal conditions. The MOF catalyst was built based on magnetic nanoparticles and UiO-66-NH2 which further modified with 2,4,6-trichloro-1,3,5-triazine and 5-phenyl tetrazole at the same time and the catalyst structure was confirmed by various techniques. This new modification has been applied to increase anchoring palladium into the support. Furthermore, the products’ yields were obtained in good to excellent for all reactions under mild conditions which result from superior activity of the synthesized heterogeneous catalyst containing palladium. Also, the magnetic property of the MOF-based catalyst makes it easy to separate from reaction mediums and reuse in the next runs.

Ni-Catalyzed C-H Cyanation of (Hetero)arenes with 2-Cyanoisothiazolidine 1,1-Dioxide as a Cyanation Reagent.

A nickel-catalyzed C-H cyanation reaction of arenes has been developed using 2-cyanoisothiazolidine 1,1-dioxide as an electrophilic cyanation reagent. Many different directing groups can be used in this cyanation to obtain a series of cyanation products with good yields. Adopting this strategy to introduce a cyano group, natural alkaloid menisporphine was successfully synthesized through cyano group conversion that further proved the practicality of this cyanation method.

Eucalyptol: A Bio-Based Solvent for the Synthesis of O,S,N-Heterocycles. Application to Hiyama Coupling, Cyanation, and Multicomponent Reactions

We report here the use of eucalyptol as a bio-based solvent for Hiyama coupling, cyanation, and multicomponent reactions on O,S,N-heterocycles. These heterocycles were chosen as targets or as starting materials given their biological potential; they play an important role in therapeutically active compounds. Once again, eucalyptol proved to be a credible and sustainable alternative to common solvents.

Application of combined cyanide sources in cyanation reactions.

The cyanation reaction is a key transformation due to the wide-ranging applications of nitrile compounds in organic chemistry. Traditionally, the cyanation reaction employs metal cyanides as cyanide sources, which are toxic and environmentally unfriendly. Very recently, many excellent examples of using combined cyanide sources as cyanating agents have been reported. This review summarizes the applications of combined cyano-group sources in a variety of cyanation reactions.

An easily fabricated palladium nanocatalyst on magnetic biochar for Suzuki–Miyaura and aryl halide cyanation reactions

A sustainable biochar material for the synthesis of a novel heterogeneous catalyst for organic reactions is reported.

Metal-mediated C-CN Bond Activation in Organic Synthesis.

Nitriles are ubiquitous versatile building blocks in organic synthesis. Common reactions of nitriles include the transformation of cyano groups into carbonyl and amine moieties. The functionalization of nitriles can also be accomplished at the alpha-position of alkanenitriles and at the ortho-position of cyanoarenes. On the other hand, the C-CN bond of nitriles has rarely been recognized as a valuable reaction site due to its thermodynamic robustness. Although it has been known for a long time in organometallic chemistry that C-CN bonds can be cleaved by transition-metal complexes, this elemental reaction had not been used in catalytic synthetic transformations of nitriles until two decades ago. This review surveys the progress of metal-catalyzed reactions of nitriles via C-CN bond activation. After introducing several different modes to activate C-CN bonds by various transition metals, catalytic reactions are categorized mainly into two parts: (i) reactions with CN as a leaving group and (ii) reactions with nitriles as a source of CN groups. Cross-coupling-type transformations with a cyano leaving group, cyanation reactions using nitriles as a nontoxic cyano source, and novel synthetic reactions such as carbocyanation are highlighted together with useful demonstrations of their utility in organic synthesis.

Convenient and Robust Metal-Free Synthesis of Benzazole-2-Ones Through the Reaction of Aniline Derivatives and Sodium Cyanate in Aqueous Medium

Benzazole-2-ones (benzimidazolones, benzothiazolones, benzoxazolones) are important derivatives of benzazole compounds that exist widely in many biologically and pharmaceutically active molecules. Furthermore, benzazole-2-one derivatives also have many applications in agrochemical and material science. Herein, a novel, practical and green synthesis of titled compounds by the reaction of aniline derivatives with inexpensive and easily accessible sodium cyanate has been reported. Good to excellent yields of products have been obtained under catalyst- and ligand-free conditions in water as solvent. This procedure avoids the use of time-consuming and tedious column chromatography and the products were easily isolated by simple extraction followed by washing with dichloromethane.