| Due to their unique properties,aryl nitriles are widely involved in the research and development of pharmaceuticals,agrochemicals and other fields.Moreover,aryl nitriles can be employed as versatile intermediates in organic synthesis.For example,they can be converted into amides,carboxylic acids,amines,aldehydes,ketones and heterocycles through the reactions of hydrolysis,reduction,nucleophilic addition and cyclization.In the other hand,transition metal catalyzed transformations have the advantages of high efficiency and superior atom economy.Therefore,the convenient synthesis of aryl nitriles catalyzed by transition metals is of great significance for chemical industry and drug manufacture.Based on our group’s valuable experience in copper-catalyzed coupling reactions,we designed and synthesized a new class of potent picolinamide ligands.With these ligands,we disclosed the cyanation of aryl halides with two different cyanide sources.Firstly,based on the Rosenmund-von Braun reaction,we conducted the cyanation of aryl bromides with low catalytic loadings of ligands and just one equivalent Cu CN.More specifically,the electron-rich heteroaryl bromines were converted into the corresponding nitriles with good yields at the temperature as low as 100℃.In comparison,copper-mediated cyanation of electron-rich bromides was difficult at such low temperature in previous reports.With these fruitful results,we also explored the potential of Rosenmund-von Braun reaction in the presence of aryl chlorides.Additionally,we studied the cyanation of aryl bromides catalyzed by Cu I with K4[Fe（CN）6]as the non-toxic cyanide source.In conclusion,we provided a practical method for the synthesis of aryl nitriles from non-activated aryl bromides. |
