A State‐of‐the‐Art Cyanation of Aryl Bromides: A Novel and Versatile Copper Catalyst System Inspired by Nature

Abstract

A general protocol for the cyanation of aryl halides with the nontoxic cyanide source K4[Fe(CN)6] using copper catalysis and a ligand system based on 1-alkylimidazoles is presented. The advantages of this system are the high selectivity, a unique substrate range, easy handling, and inexpensive reagents.

The Synthesis of Novel Isoindoline Nitroxides Bearing Water‐Solubilising Functionality

“…Scheme 2. As an alternative, we sought to apply a recently described procedure using copper(I) iodide and n-butylimidazole (nBuImi) which facilitates the conversion of aryl bromides to benzonitriles in the presence of non-toxic potassium hexacyanoferrate. [28] Initial attempts to convert the dibromo nitroxide to the desired dinitrile nitroxide 12 under these conditions led to a complex mixture of products which may have resulted from the interaction of copper(I) with the nitroxide moiety. Notably, the analogous copper(I)-catalysed coupling reaction of the dibromoamine 11 proceeded smoothly and gave the desired dinitrile 13 in good yield (78 %) following recrystallisation to remove an n-butylimidazole side-product [possibly a copper(I)-n-butylimidazole complex, which could not be removed following acid-base work-up or column chromatography].…”

Increasing the Scope of Palladium‐Catalyzed Cyanations of Aryl Chlorides

“…[6b] Using copper as catalyst metal in the presence of 1-alkylimidazoles as additives functionalized aryl and heteroaryl bromides were converted in high yields, [9] however aryl chlorides reacted only in rare cases. Nevertheless, initial success in the cyanation of aryl chlorides has been achieved.…”

Modern Synthetic Approaches to Phthalonitriles with Special Emphasis on Transition-Metal Catalyzed Cyanation Reactions

“…as ligands. [29] Wide range of substrates was studied, among them -o-dibromobenzene, which was converted into phthalonitrile in 78 % yield. Surprisingly, only very few papers report about synthesis of phthalonitriles via this promising protocol.…”