C–CN bond formation: an overview of diverse strategies
Nitrile or cyano compounds are an important part of structural motifs in dyes, agrochemicals, medicinal compounds, and electronic materials. Also, aryl nitrile is an important intermediate in the preparation of numerous compounds via transformations such as hydrolysis, hydration, reduction, cycloadditions, and nucleophilic additions. Such methods are beneficial for introducing sensitive functional groups in various positions in the multi-step synthesis of natural products and medicinal compounds. In the past decades, various cyanation methods have been reported in the vast arena of chemistry, which have made several building blocks accessible. Previously reported cyanation reviews, letters, and perspectives are written in parts. Thus, today a comprehensive review that will be able to guide readers through the vast pool of C–CN bond forming reactions via different approaches is obligatory. The present feature article depicts the various areas of cyanation methodologies that are based on the metal catalyst used, directed, non-directed, electrochemical, photochemical, asymmetric, and radical based approaches. This feature article will serve as a comprehensive tool to navigate the C–CN (cyanation) reactions across the vast area in synthetic chemistry.