Copper-catalyzed cyanation of aryl iodide with the combined cyanide source of urea and DMSO

A simple copper-catalyzed cyanation of aryl iodide with the combination of urea and dimethyl sulfoxide as a cyanide source is achieved, providing nitriles in moderate to good yields. This new approach represents an exceedingly practical and safe method for the synthesis of aryl nitriles.     

Copper-mediated cyanation of aryl halide with the combined cyanide source

A simple copper-mediated cyanation of aryl halide with the combination of ammonium bicarbonate and N,N-dimethylformamide as a cyanide source is achieved, providing nitriles in moderate to good yields. This new approach represents an exceedingly practical and safe method for the synthesis of aryl nitriles.     

Palladium-catalyzed cyanation of aryl bromides promoted by low-level organotin compounds

A novel method for palladium-catalyzed cyanation of aryl bromides promoted by low-level tri-n-butyltin chloride or cyanide is described. The method features low catalyst loading and mild reaction conditions. KCN is used as the cyanide source. Only trace levels of the tri-n-butyltin compound are required to achieve high conversion and yield in the cyanation of aryl bromides, iodides, and triflates.     

A mild and efficient palladium-catalyzed cyanation of aryl chlorides with K4[Fe(CN)6

An efficient palladium-catalyzed cyanation of aryl chlorides is established. In the presence of a highly effective Pd/CM-phos catalyst, cyanation of aryl chlorides proceeds at 70 °C in general, which is the mildest reaction temperature achieved so far for this process. Common functional groups such as keto, aldehyde, ester, nitrile and -NH(2), and heterocyclic coupling partners including N-H indoles are well tolerated. Moreover, a sterically hindered nonactivated ortho,ortho-disubstituted electrophile is shown to be a feasible coupling partner in cyanation.     

Ag/Cu-mediated decarboxylative cyanation of aryl carboxylic acids with K4Fe(CN)6 under aerobic conditions

A method for facile synthesis of aryl nitriles has been well established via Ag/Cu-mediated decarboxylative cyanation of benzoic acids with K₄Fe(CN)₆ under aerobic conditions. The approach of using readily accessible aryl carboxylic acids and green K₄Fe(CN)₆ as starting material provides a feasible alternative to previous cyanation protocols. Control experiments revealed the key role of Cu for the process and excluded the possibility of a radical mechanism for the transformation.     

Cyanide-Free Cyanation of sp2 and sp-Carbon Atoms by an Oxazole-Based Masked CN Source Using Flow Microreactors

This work reports a cyanide-free continuous-flow process for cyanation of sp² and sp carbons to synthesize aryl, vinyl and acetylenic nitriles from (5-methyl-2-phenyloxazol-4-yl) boronic acid [OxBA] reagent as a sole source of carbon-bound masked −CN source. Non-toxic and stable OxBA reagent is generated by lithiation-borylation of bromo-oxazole, and the consecutive Suzuki-Miyaura cross-coupling with aryl, vinyl, or acetylenic halides and demasking [4+2]/retro-[4+2] sequence were successfully accomplished to give the desired cyano compounds with reasonably good yields in a four-step flow manner. A unique feature of this cyanation protocol in flow enables to cyanate a variety of sp² and sp carbons to produce a broad spectrum of aryl acetonitrile. It is envisaged that the OxBA based cyanation would replace existing unstable and toxic approaches as well as non-toxic cyanation using two different sources of “C” and “N” to incorporate the −CN group.     

Copper-and Silver-Mediated Cyanation of Aryl Iodides Using DDQ as Cyanide Source

A new copper and silver‐mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, providing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles.     

Mild and efficient copper-catalyzed cyanation of aryl iodides and bromides

An efficient copper-catalyzed cyanation of aryl iodides and bromides is reported. Our system combines catalytic amounts of both copper salts and chelating ligands. The latter, which have potential nitrogen- and/or oxygen-binding sites, have never previously been used in this type of reaction. A protocol has been developed that enables the cyanation of aryl bromides through the copper-catalyzed in situ production of the corresponding aryl iodides using catalytic amounts of potassium iodide. Aryl nitriles are obtained in good yields and excellent selectivities in relatively mild conditions (110 degrees C) compared with the Rosenmund-von Braun cyanation reaction. Furthermore, the reaction is compatible with a wide range of functional groups including nitro and amino substituents. The protocol reported herein involves two main innovations: the use of catalytic amounts of ligands and the use of acetone cyanohydrin as the cyanating agent in copper-mediated cyanation reactions.     

Ligand-free palladium-catalyzed cyanation of aryl halides

[reaction: see text] A practical, ligand-free cyanation of aryl bromides that utilizes as little as 0.1 mol % Pd(OAc)(2) in combination with a nontoxic cyanide source, M(4)[Fe(CN)(6)] (M = K, Na), is described. The reactions are performed in DMAC at 120 degrees C and provide the corresponding aryl nitrile in 83-96% yield, typically in less than 5 h. TON values of up to 7100 were attained.     

Progress in the palladium-catalyzed cyanation of aryl chlorides

The development of new palladium catalysts for the cyanation of various aryl and heteroaryl chlorides is described. The combination of amine co-catalysts with chelating phosphine ligands, for example, 1,4-bis(diphenylphosphino)butane (dppb) or 1,5-bis(diphenylphosphino)pentane (dpppe), allows an efficient cyanation of chloroarenes with simple potassium cyanide. General palladium-catalyzed cyanation of nonactivated and deactivated chloroarenes is possible for the first time. Studies of the oxidative addition of aryl halides to palladium triphenylphosphine complexes in the presence and absence of amines suggest that the co-catalyst is capable of preventing catalyst deactivation caused by the presence of excess cyanide ions in solution.     

Mild and general methods for the palladium-catalyzed cyanation of aryl and heteroaryl chlorides

[reaction: see text] New methods for the palladium-catalyzed cyanation of aryl and heteroaryl chlorides have been developed, featuring sterically demanding, electron-rich phosphines. Highly challenging electron-rich aryl chlorides, in addition to electron-neutral and electron-deficient substrates, as well as nitrogen- and sulfur-containing heteroaryl chlorides can all undergo efficient cyanation under relatively mild conditions using readily available materials. In terms of substrate scope and temperature, these methods compare very favorably with the state-of-the-art cyanations of aryl chlorides.     

An Improved Procedure for the Cyanation of Aryl Triflates: A Convenient Synthesis of 6-Cyano-1,2,3,4-Tetrahydroisoquinoline

A short synthesis of 6-cyano-1,2,3,4-tetrahydroisoquinoline is presented. The key step is an improved method of aryl triflate cyanation employing zinc(II)cyanide as the cyanide source.     

Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate) catalyzed Suzuki, Heck, Sonogashira, and cyanation reactions

Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate): a structurally well-defined O-containing transition metal complex is reported as an efficient catalyst for Suzuki, Heck, and Sonogashira cross-coupling reactions. The protocol was also applied successfully for cyanation of aryl halides under milder operating conditions. The system tolerated the coupling of various aryl halides with alkenes, alkynes, and organoboronic acid along with the cyanation of aryl halides providing good to excellent yields of desired products.     

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.     

The palladium-catalyzed desulfitative cyanation of arenesulfonyl chlorides and sodium sulfinates

A palladium-catalyzed desulfitative cyanation of arenesulfonyl chlorides and sodium sulfinates has been developed, providing aryl nitriles in moderate to excellent yields. It represents a facile procedure to access aryl nitriles.     

A facile microwave-assisted palladium-catalyzed cyanation of aryl chlorides

We report an efficient method for the preparation of aryl nitriles from aryl chlorides under either microwave assisted or thermal conditions. A catalyst system comprising tris(dibenzylidene acetone)dipalladium (Pd₂(dba)₃) and 2-(2′,6′-dimethoxybiphenyl)dicyclohexylphosphine (S-Phos) is shown to effectively promote cyanation of various aryl chlorides with Zn(CN)₂ as the cyanide source.     

Copper-mediated cyanation of aryl boronic acids using benzyl cyanide

An efficient copper-mediated synthesis of aryl nitriles from aryl boronic acids has been achieved using benzyl cyanide as a user-friendly cyanide source. Various aryl boronic acids underwent the reaction smoothly, affording the corresponding aryl nitriles in moderate to good yields. tert-Butyl hydroperoxide (TBHP) was found to be a critical agent facilitating the cyanation reaction.     

An expedient Pd/DBU mediated cyanation of aryl/heteroaryl bromides with K4[Fe(CN)6

A practical Pd(PPh(3))(4)/DBU catalytic system for the synthesis of pharmaceutically relevant aminopyridine nitrile intermediates, as well as a variety of other aryl nitriles using non-toxic K(4)[Fe(CN)(6)] has been developed. The key features of our new protocol for cyanation lie in that the reaction can be carried out with readily available Pd(PPh(3))(4) under mild and green conditions, even without the assistance of other ligands.     

Rhodium‐Catalyzed Transnitrilation of Aryl Boronic Acids with Dimethylmalononitrile

An efficient transnitrilation of aryl boronic acids with dimethylmalononitrile (DMMN) is described. This rhodium‐catalyzed electrophilic cyanation presents a novel approach to prepare aryl nitriles by using a carbon‐bound cyanating reagent which undergoes cross‐coupling with the aryl boronic acid. The reaction expands the degree of functional‐group compatibility exhibited by the transnitrilation of aryl Grignard and aryllithium reagents. A variety of aryl boronic acid derivatives and dialkylmalononitriles were amenable to the transnitrilation.     

Microwave-enhanced and ligand-free copper-catalyzed cyanation of aryl halides with K4[Fe(CN)6] in water

Copper-catalyzed cyanation of aryl halides was improved to be more economical and environmentally friendly by using water as the solvent and ligand-free Cu(OAc)₂·H₂O as the catalyst under microwave heating. The suggested methodology was applicable to a wide range of substrates including aryl iodides and activated aryl bromides.