Radical Decyanations of Unactivated Carbon‐CN Bonds: Recent Achievements and Mechanistic Studies

Abstract Decyanation is an important process in the synthesis of aromatic molecules in the studies of pharmaceutical research, medical and materials sciences. In late‐stage modifications of privileged carbo/heterocyclic scaffolds, radical‐type decyanation techniques have been devised to date. As a result, the chemistry of cyano‐involved conversions, a hotly debated subject over the past few decades, has advanced significantly. The cyano group (CN), on the other hand, has rarely been acknowledged as a good reaction site due to its thermodynamic robustness. The most recent advancements in catalytic radical decyanation protocols that CN behaved as a leaving group has made are surveyed in this article. Following the introduction of a number of different reaction modes, the catalytic reactions that are used to activate the C−CN bonds are primarily categorized, and the text herein are divided into three groups: (1) photo‐catalyzed decyanation transformations, (2) electro‐catalyzed decyanation transformations, and (3) transition‐metal‐catalyzed or metal‐free decyanation transformations. With an emphasis on the catalytic systems and synthetic applications in C−CN bond activation, this review will provide the readers with an overview of decyanation chemistry in radical reactions.