Organic transformations of isocyanides classified by their activation strategies

Isocyanides have been extensively utilized in organic synthesis to construct valuable chemical structures. Classical Ugi 4-component reaction is the robust method to access diversely functionalized peptoids. By using well-established cyclization techniques, a variety of nitrogen heterocycles from commercially accessible compounds have been efficiently synthesized. Several transition metal-catalyzed processes have been developed to utilize isocyanide as a useful carbonyl nitrogen synthon. Recently developed synthetic methods, such as C-H bond activation and visible-light photocatalysis, have been adopted to the isocyanide chemistry to enhance the efficiency, availability, and novelty of the chemical processes. This review summarizes the reactivity of isocyanide classified by the activation modes of electrophilic, nucleophilic, and radical species, together with the seminal discoveries and recent advances in the past 10 years.