Recent Advances in Radical-Initiated C(sp³)-H Bond Oxidative Functionalization of Alkyl Nitriles

Chemoselective functionalizations of intrinsically less reactive C(sp³)-H bonds of alkyl nitriles are of particular interest to the chemical community because these strategies provide opportunities for the introduction of important cyanoalkyl groups onto target frameworks in a step-economical fashion. In recent years, the introduction of nitrile-containing alkyl radicals in tandem radical additions and oxidative couplings has inarguably brought chemists a new radical reaction platform for the diverse synthesis of natural products and pharmaceuticals. Compared with the wide applications of various C-centered radicals adjacent to a heteroatom, however, nitrile-containing alkyl radicals remain largely unexplored. New methods for C(sp³)-H bond oxidative functionalization of alkyl nitriles and new mechanistic manifolds would result in the development of a broad range of novel reactions. Therefore, this review will give an overview of various types of radical cyanoalkylation using the key alkyl nitrile reactants, which lie beyond traditional coupling chemistry.