Revisited the mechanism of cobalt(III) catalyzed cyanation of arenes and heteroarenes: A DFT study

Abstract

Transition metal catalyzed cyanation of arenes and heteroarenes by CH activation is an attractive process for functionalization of aromatic system. One such reaction under the catalysis of cobalt complex using N-cyano-N-phenyl-p-toluenesulfonamide as a cyanating reagent was studied theoretically. Metal mediated cyanation of aromatic ring involving one and more acetic acid have been explored. Our finding reveals that during the metal mediated activation of CH bond, presence of two acetic acid, increase the activation energy of the proton abstraction step. Comparison of the energy profile diagrams for single and double acetic acid mediated steps shows that the pathway, assisted by single acetic acid, is energetically more favorable. The calculated apparent activation barrier of the reaction is also consistent with the experimental report and it also shows high temperature (120 °C) has been needed to carry out the reaction.