Metal-catalyzed reactions of organic nitriles and boronic acids to access diverse functionality

Abstract

The nitrile or cyano (-CN) group is one of the most appreciated and effective functional groups in organic synthesis having a polar unsaturated C-N triple bond. Despite sufficient stability and...

The Renaissance of Organo Nitriles in Organic Synthesis

“…During the process, the nitrile group acts as an electrophile and undergoes addition with aryl nucleophile generated from the coupling partners. A comprehensive review pertaining to the metal‐catalyzed addition of arylboronic acids to nitriles has been very recently reported by our group [62] . Therefore the present review focus on other cascade reactions of nitriles excluding arylboronic acids.…”

“…A comprehensive review pertaining to the metal-catalyzed addition of arylboronic acids to nitriles has been very recently reported by our group. [62] Therefore the present review focus on other cascade reactions of nitriles excluding arylboronic acids. For example, in 2009, the Nagasawa group reported a Cu(I)catalyzed synthesis of 1,2,4-triazoles (131) through the addition of 2-aminopyridines (130) to the nitriles (129) followed by oxidative cyclization leading to CÀ N and NÀ N bonds formation (Scheme 54).…”

Chalcogen Bonding in the Decoration of the Secondary Coordination Sphere of Copper(II) Complexes: Activation of Nitriles, the Auxiliary Ligand Substituent Effect

“…On the other hand, the activation of a CN triple bond at an organonitrile is an important synthetic operation for the access of new substrates, multifunctional drugs, supramolecular aggregates, catalysts, ionophores, etc. ,,− The H-bond (metal-free) or coordination (metal-mediated) bond-assisted regioselective activation of the CN group at arylhydrazones of malononitrile produces a variety of amidines, carboxamides, iminoesters, or multinuclear transition metal complexes, which depend on the nucleophiles, metal centers, and reaction conditions used. ,,, For instance, herein, our preliminary experiments show that metal-free activation of CN in the arylhydrazones of malononitrile can be extended for the synthesis of chiral water-soluble arylhydrazones by use of chiral amines as nucleophiles (Scheme a). In addition, metal-mediated activation of CN in organonitriles in the presence of auxiliary ligands is a prominent synthetic pathway in one-pot synthesis of transition metal complexes, where their supramolecular structures as well as magnetic and catalytic properties are greatly affected by these secondary ligands. ,,, Not only the coordination modes but also the substituents at auxiliary ligands may have a great influence on the strength of intermolecular interactions in the crystal structure of those coordination compounds. , …”

Copper-Catalyzed, Ligand-Controlled N(sp3)- or N(sp)-Selective Arylation of Cyanamides

“…Cyanamides are versatile building blocks containing three reactive sites: a carbon atom (sp-hybridized) and two nitrogen atoms (sp- and sp 3 -hybridized) . This dense array of electrophilic and nucleophilic positions in cyanamides provides a unique reactivity and allows a myriad of ionic, radical, pericyclic, and metal-catalyzed transformations. − Moreover, it does also confer to cyanamides the ability to act as efficient ligands for various transition metals. − In line with our interest in copper-catalyzed reactions , and transition metal-catalyzed reactions of cyanamides, , we became interested in their N-arylation and more particularly in the control over the chemoselectivity (sp- vs sp 3 -hybridized nitrogen atom) of the process.…”