Palladium-Catalyzed Cyanation of Aryl Halides with CuSCN

ZnCo2O4@g-C3N4@Cu as a new and highly efficient heterogeneous photocatalyst for visible light-induced cyanation and Mizoroki-Heck cross-coupling reactions

Conducting C-C cross-coupling reactions under convenient and mild conditions remains extremely challenging in traditional organic synthesis. In this study, ZnCo2O4@g-C3N4@Cu exhibited extraordinary photocatalytic performance as a new visible light harvesting heterogeneous copper-based photocatalyst in cyanation and Mizoroki-Heck visible-light-driven cross-coupling reactions at room temperature and in air. Surprisingly, by this method, the cyanation and Mizoroki-Heck cross-coupling reactions of various iodo-, bromo- and also the challenging chloroarenes with respectively K4[Fe(CN)6]·3H2O and olefins produced promising results in a sustainable and mild media. The significant photocatalytic performance of ZnCo2O4@g-C3N4@Cu arises from the synergistic optical properties of ZnCo2O4, g-C3N4, and Cu. These components can enhance the charge carrier generation and considerably reduce the recombination rate of photogenerated electron-hole pairs. No need to use heat or additives, applying an economical and benign light source, utilizing an environmentally compatible solvent, facile and low-cost photocatalytic approach, aerial conditions, high stability and convenient recyclability of the photocatalyst are the remarkable highlights of this methodology. Moreover, this platform exhibited the ability to be performed on a large scale, which is considered an important issue in industrial and pharmaceutical use. It is worth noting that this is the first time that a heterogeneous copper-based photocatalyst has been employed in visible light-promoted cyanation reactions of aryl halides.

Recent investigations into deborylative (thio-/seleno-) cyanation of aryl boronic acids

In this review, we intend to summarize the most important discoveries in the deborylative (thio-/seleno-) cyanation of aryl boronic acids from 2006 to the end of 2023. Thus, the review is divided into three parts. The first section focuses exclusively on cyanation of aryl boronic acids into aryl nitriles. The second section covers the available literature on the synthesis of aryl thiocyanates through thiocyanation of respective aryl boronic acids. The third will discuss selenocyanation of aryl boronic acids into aryl selenocyanates.

Oxidative Radical Transnitrilation of Arylboronic Acids with Trityl Isocyanide

We report a radical transnitrilation of arylboronic acids with trityl isocyanide in the presence of manganese(III) acetate. Many functional groups can be tolerated in this transformation, and a special positive effect of benzoic acid in this reaction has been observed.

Visible-Light-Mediated Additive-Free Decarboxylative Ketonization Reaction of Acrylic Acids: An Access to α-Thiocyanate Ketones

Visible-light-mediated additive-free decarboxylative functionalization of acrylic acids has been developed. The reaction uses inexpensive organic dye 9,10-dicyanoanthracene as a photocatalyst and uses the ubiquitous dioxygen as both an oxygen source and an oxidant. Through this mild and environmentally friendly method, a series of important α-thiocyanate ketones can be generated from easily available acrylic acids and ammonium thiocyanate. In addition, the facile transformation of product α-thiocyanate ketones makes this method have great potential for application in organic and pharmaceutical chemistry.

Cyanation: a photochemical approach and applications in organic synthesis

This review summarises the photocatalytic cyanation strategies to construct C(sp²)–CN, C(sp³)–CN and X–CN (X = N, S) bonds.

Tandem Strecker/C(sp3)–H amination reactions for the construction of cyanide-functionalized imidazo[1,5-a]pyridines with NH4SCN as a cyanating agent

An I2O5-mediated multicomponent reaction that allows the single-step construction of cyano-functionalized imidazo[1,5-a]pyridines with molecular diversity was realized for the first time.

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.

Rh(III)-Catalyzed C-H Cyanation of 2H-Indazole with N-Cyano-N-phenyl-p-toluenesulfonamide

A Rh(III)-catalyzed direct cyanation of 2H-indazoles with N-cyano-N-phenyl-p-toluenesulfonamide has been realized via a chelation-assisted strategy. The methodology enables regioselective access to various ortho-cyanated phenylindazoles in good yields with a broad substrate scope and good functional group compatibility. The obtained cyanated indazoles could further be converted into other value-added chemicals. Importantly, the current protocol is featured with several characteristics, including a novel cyanating agent, good regioselectivity, and operational convenience.

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes

In this review, direct cyanation, hydrocyanation, dicyanation, cyanofunctionalization and other cyanation reactions of alkynes were highlighted. Firstly, the use of nitriles and development of cyanation was simply introduced. After presenting the natural properties of alkynes, cyanation reactions of alkynes were classified and introduced in detail. Transition metal catalysed direct cyanation and hydrocyanation of alkynes gave alkynyl cyanides and alkenyl nitriles in good yields. Dicyanation of alkynes produced 1,2-dicyano adducts. Cyanofunctionalization of alkynes afforded functional cyanated compounds. Thiocyanation and selenocyanation yielded the expected functional vinylthiocyanates and vinylselenocyanates. A plausible reaction mechanism is presented if available.

One-pot regioselective C-H activation iodination-cyanation of 2,4-diarylquinazolines using malononitrile as a cyano source

A one-pot cyanation of 2,4-arylquinazoline with NIS and malononitrile has been developed. The one-pot reaction includes two steps. The Rh-catalyzed selective C-H activation/iodization of 2,4-diarylquinazoline with NIS, and then Cu-catalyzed cyanation of the corresponding iodinated intermediate with malononitrile to selectively give 2-(2-cyanoaryl)-4-arylquinazolines or 2-(2,6-dicyanoaryl)-4-arylquinazolines in good to excellent yields.

Perylenequinonoid-Catalyzed [4 + 1] and [4 + 2] Annulations of Azoalkenes: Photocatalytic Access to 1,2,3-Thiadiazole/1,4,5,6-Tetrahydropyridazine Derivatives

Nitrogen-containing heterocycles are especially considered "privileged" structural scaffolds for the development of new drugs. However, traditional methods of organic synthesis are mainly based on thermal cycloaddition reaction; thus, the exploration of new strategies for the rapid assembly of N-heterocycles under mild conditions is highly desirable. Here, we developed a new method that visible light along with 1 mol % cercosporin, which is one of the perylenequinonoid pigments with excellent properties of photosensitization and can be easily produced by a new isolated endophytic fungus Cercospora sp. JNU001 strain with high yield through microbial fermentation, catalyzes the synthesis of 1,2,3-thiadiazoles and 1,4,5,6-tetrahydropyridazines by a photocatalytic process with good regioselectivity and broad functional-group compatibility under mild conditions. Thus, a bridge between microbial fermentation and organic photocatalysis for the construction of nitrogen-containing heterocycles was set up in a sustainable, environmentally friendly manner.

Non-toxic cyanide sources and cyanating agents

The present review gives an overview over non-toxic cyanation agents and cyanide sources used in the synthesis of structurally diverse products containing the nitrile function. Nucleophilic as well as electrophilic agents/systems that transfer the entire CN-group were taken in consideration. Reactions in which a preexisting carbon functionality is transformed into a nitrile function by addition of nitrogen are however not covered here.

Oxidative cyanation of N-aryltetrahydroisoquinoline induced by visible light for the synthesis of α-aminonitrile using potassium thiocyanate as a “CN” agent

A novel method for the synthesis of α-aminonitrile, through visible-light-induced oxidative cyanation of N-aryltetrahydroisoquinoline with potassium thiocyanate, has been developed.

Employing thiocyanate salts as a nitrogen source via CN bond cleavage: divergent synthesis of α-ketoamides and 2-acyloxazoles

A switchable procedure for the synthesis of α-ketoamides and 2-acyloxazoles from aryl methyl ketones and thiocyanate salts is reported.

Metal-free oxidative [2+2+1] heteroannulation of 1,7-enynes with thiocyanates toward thieno[3,4-c]quinolin-4(5H)-ones

A new metal-free oxidative [2+2+1] heteroannulation of 1,7-enynes with thiocyanates for producing thieno[3,4-c]quinolin-4(5H)-ones is presented. This reaction employs benzoylperoxide (BPO) as the oxidant and sodium thiocyanate as the sulfur source to enable the formation of three chemical bonds, two C-S bonds and one C-C bond, in a single reaction, and represents a new, practical access to S-heterocycles with the avoidance of the use of metal catalysts and excess bases.

Copper catalyzed cyanation through CC bond cleavage of gem-aryl dibromide followed by second cyanation of iodoarene by a released CN unit

A new approach for the synthesis of aryl cyanides through CC cleavage of styrenyl gem-dibromide has been achieved.

Copper-free Sandmeyer cyanation of arenediazonium o-benzenedisulfonimides

The first example of a copper-free Sandmeyer cyanodediazoniation carried out using arenediazonium o-benzenedisulfonimide and tetrabutylammonium cyanide is reported in this paper.

Fabrication of Pd Nanoparticles Embedded C@Fe3O4 Core-Shell Hybrid Nanospheres: An Efficient Catalyst for Cyanation in Aryl Halides

Isolated chemical reactors were fabricated by integrating catalytically active sites (Pd) with magnetic functionality (Fe3O4) along with carbon while preserving the constituents functional properties to realize the structure-property relationship of Pd by comparing the catalytic activity of spherical Pd NPs with cubical Pd NPs for cyanation in aryl halides using K4[Fe(CN)6] as a green cyanating agent to yield corresponding nitriles. The superior catalytic reactivity of the cubical Pd NPs is attributed to the larger number of {100} surface facets. The TEM images of reused catalyst shows the change in structure from cubical to spherical nanoparticles, attributed to the efficient leaching susceptibility of Pd {100} surface facets. The cubical Pd NPs on carbon@Fe3O4 is attractive in view of its high catalytic efficiency, easy synthesis, magnetic separability, environmental friendliness, high stability, gram scale applicability, and reusability.