Palladium-catalyzed Cyanation Of Aryl Halides Research Articles

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.

A New CN Source for the Palladium-Catalyzed Cyanation of Aryl Halides

Key words cyanation - palladium catalysis - aryl halides - formamide - cyanuric chloride - benzonitriles

Recent advances and prospects in the palladium-catalyzed cyanation of aryl halides.

Aryl nitriles are compounds with wide significance. They have made their own space in various sectors including pharmaceuticals, industries, natural product chemistry, and so on. Furthermore, they are also key intermediates in various transformations in organic chemistry. Transition metal-catalyzed cyanation reactions have proved to be a better replacement for the existing traditional synthetic strategies for aryl nitriles. Palladium is one of the most studied transition metals other than copper and nickel owing to its wide functional group compatibility and catalytic efficacy. There have been drastic developments in the field of palladium-catalyzed cyanation since its discovery in the 1973. This review summarizes the recent developments in the palladium-catalyzed cyanation of aryl halides and covers literature from 2012–2020.

Pd Nanocatalyst Adorning Coral Reef Nanocomposite for the Synthesis of Nitriles: Utility of Cucurbita pepo Leaf Extract as a Stabilizing and Reducing Agent.

A simple procedure for the palladium-catalyzed cyanation of aryl halides is described via a nucleophilic non-toxic cyanide source, K4[Fe(CN)6] in the presence of Pd/coral reef nanocomposite as a heterogeneous catalyst; the protocol provides a useful and easy method for the synthesis of aryl nitriles that are generated from the corresponding variant aryl halides, with sodium carbonate as a base. The nanocatalyst was prepared by a biological process using aqueous extract of leaves of Cucurbita pepo as a stabilizing and reducing agent and coral reef as a natural support, without deploying any hazardous chemicals. The catalyst, that is easily separable from the reaction mixture and reused multiple times, was characterized by FT-IR (Fourier-Transform Infrared Spectroscopy), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), XRD (X-ray Diffraction), TEM (Transmission Electron Microscopy), FE-SEM (Field Emission Scanning Electron Microscopy), EDS (Energy Dispersive X-ray Spectroscopy) and elemental mapping.

Palladium-Catalyzed Safe Cyanation of Aryl Iodides with Hexamethylenetetramine.

A palladium-catalyzed cyanation of aryl halides with hexamethylenetetramine as a safe cyanide source is achieved, providing aromatic nitriles in moderate to good yields. This approach shows good functional group compatibilities and avoids the use of toxic cyanide source.

ChemInform Abstract: A Homogeneous Method for the Conveniently Scalable Palladium‐ and Nickel‐Catalyzed Cyanation of Aryl Halides.

Homogeneous conditions for the palladium-catalyzed cyanation of aryl halides were developed. This new system features a broad scope of aryl chlorides and bromides, uses 2-propanol or 1-butanol as solvent, and is readily scalable. The same conditions can also provide simple benzonitriles using the recently developed (TMEDA)NiCl(o-tolyl) precatalyst in conjunction with 1,1′-bis(diphenylphosphino)ferrocene (dppf) as a ligand.

A Homogeneous Method for the Conveniently Scalable Palladium- and Nickel-Catalyzed Cyanation of Aryl Halides

Homogeneous conditions for the palladium-catalyzed cyanation of aryl halides were developed. This new system features a broad scope of aryl chlorides and bromides, uses 2-propanol or 1-butanol as solvent, and is readily scalable. The same conditions can also provide simple benzonitriles using the recently developed (TMEDA)NiCl(o-tolyl) precatalyst in conjunction with 1,1′-bis(diphenylphosphino)ferrocene (dppf) as a ligand.

ChemInform Abstract: Cyanation of Unactivated Aryl Chlorides and Aryl Mesylates Catalyzed by Palladium and Hemilabile MOP‐Type Ligands.

Palladium-catalyzed cyanation of aryl halides and pseudo halides with potassium hexacyanoferrate is described employing the hemilabile, bulky, and electron-rich MOP-type ligands. When the mixture of t-BuOH and H2O was used as the solvent and K2CO3 as the base, the MOP-type ligands showed high efficiency for the palladium-catalyzed cyanation. The effect of ligand structure was studied in detail, and 2-di-tert-butylphosphino-2′-isopropoxy-1,1′-binaphthyl was the more effective for the cyanation. The catalyst system allows the cyanation of unactivated aryl chlorides, and even aryl mesylates to occur in good yields. Furthermore, the reactivity of different arylated reagents in the catalytic system was found to be: ArBr > ArCl >> ArOMs > ArOSO2Im > ArOSO2NMe2.

Cyanation of Unactivated Aryl Chlorides and Aryl Mesylates Catalyzed by Palladium and Hemilabile MOP-Type Ligands

Palladium-catalyzed cyanation of aryl halides and pseudo halides with potassium hexacyanoferrate is described employing the hemilabile, bulky, and electron-rich MOP-type ligands. When the mixture of <i>t</i>-BuOH and H₂O was used as the solvent and K₂CO₃ as the base, the MOP-type ligands showed high efficiency for the palladium-catalyzed cyanation. The effect of ligand structure was studied in detail, and 2-di-<i>tert</i>-butylphosphino-2′-isopropoxy-1,1′-binaphthyl was the more effective for the cyanation. The catalyst system allows the cyanation of unactivated aryl chlorides, and even aryl mesylates to occur in good yields. Furthermore, the reactivity of different arylated reagents in the catalytic system was found to be: ArBr > ArCl >> ArOMs > ArOSO₂Im > ArOSO₂NMe₂.

ChemInform Abstract: Palladium‐Catalyzed Cyanation of Aryl Halides with CuSCN.

A palladium-catalyzed cyanation of aryl halides and borons has been developed by employing cuprous thiocyanate as a safe cyanide source. This protocol avoids the use of a highly toxic cyanide source, providing aromatic nitriles in moderate to good yields with good functional tolerance.

Palladium-Catalyzed Cyanation of Aryl Halides with CuSCN

A palladium-catalyzed cyanation of aryl halides and borons has been developed by employing cuprous thiocyanate as a safe cyanide source. This protocol avoids the use of a highly toxic cyanide source, providing aromatic nitriles in moderate to good yields with good functional tolerance.

Ethyl Cyanoacetate: A New Cyanating Agent for the Palladium-Catalyzed Cyanation of Aryl Halides

A new Pd-catalyzed cyanation reaction has been discovered using ethyl cyanoacetate as the cyanating reagent. A variety of electron-rich and electron-deficient aryl halides were efficiently converted into their corresponding nitriles in good to excellent yields.

Recent developments and perspectives in palladium-catalyzed cyanation of aryl halides: synthesis of benzonitriles

The palladium-catalyzed cyanation of Ar-X (X = I, Br, Cl, OTf, and H) allows for an efficient access towards benzonitriles. After its discovery in 1973 and following significant improvements in recent decades, this methodology has become nowadays the most popular for preparation of substituted aromatic nitriles. In this critical review, we summarize the important developments in this area from 2000 until 2010 (151 references).

Development of Pd/C-Catalyzed Cyanation of Aryl Halides

A practical method for palladium-catalyzed cyanation of aryl halides using Pd/C is described. The new method can be applied to a variety of aryl bromide and active aryl chloride substrates to effect efficient conversions. The process features many advantages over existing cyanation conditions and the practical utility of the process has been demonstrated on scale.

Development of an Open-Air and Robust Method for Large-Scale Palladium-Catalyzed Cyanation of Aryl Halides: The Use of i-PrOH to Prevent Catalyst Poisoning by Oxygen

Palladium-catalyzed cyanation of aryl halides is an often capricious reaction and lacks robustness due to catalyst poisoning by oxygen. In this report, an open-air and robust method for large-scale cyanation was developed and the use of commercially available i-propanol as an additive was critical for achieving the open-air, robust and scaleable process. Under the protection by i-propanol, the catalyst life was significantly prolonged.

Palladium-catalyzed cyanation of aryl halides using K 4[Fe(CN) 6] as cyanide source, water as solvent, and microwave heating

A methodology for the cyanation of aryl iodides and activated aryl bromides is reported using water as the solvent and K 4[Fe(CN) 6] as the cyanide source. Reactions are complete within 20 min.

The Synthesis of Poly-Nitrile Aromatic and Oligopyridine Ligands Via Palladium-Catalyzed Cyanation of Aryl Halides

Modification of Beller’s palladium-catalyzed cyanation procedure for simple aromatic halides leads to a versatile and rapid route to complex multi-nitrile aryl and oligopyridyl ligands that improves on known literature methods. By heating the reagents in the high boiling solvent mesitylene to reflux temperatures at ambient pressure, we have observed the conversion of halogenated precursors to the corresponding nitrile compounds. The resulting compounds can be precipitated from CH2Cl2 solutions of the reaction mixtures and isolated as pure compounds in moderate to high yields. The current approach offers a safer alternative to the pressure tube method, as it does not involve the use of KCN at high pressures.

Improving Palladium‐Catalyzed Cyanation of Aryl Halides: Development of a State‐of‐the‐Art Methodology Using Potassium Hexacyanoferrate(II) as Cyanating Agent.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Potassium Hexacyanoferrate(II) — A New Cyanating Agent for the Palladium‐Catalyzed Cyanation of Aryl Halides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Improving palladium-catalyzed cyanation of aryl halides: development of a state-of-the-art methodology using potassium hexacyanoferrate(II) as cyanating agent

Benzonitriles are easily accessible via palladium-catalyzed cyanation of aryl halides using potassium hexacyanoferrate(II) as cyanide source. This method is applicable on both activated and deactivated aryl and heteroaryl bromides and activated chlorides giving the corresponding benzonitriles in good to excellent yield. Advantageously, the used cyanating agent is non-toxic and cheap. The presented catalyst system is rather simple and it is not necessary to add expensive phosphines, making the novel method also attractive for industrial applications.