α-C–H functionalization of tertiary amines catalyzed/promoted by molecular iodine/derivatives

This review article focuses on the functionalization of α-C–H bonds of tertiary amines via C–H activation catalyzed by iodine or its derivatives. Recently, transition metal-free C–H functionalizations in organic synthesis have been considered as extremely important due to their environmentally friendly nature. Organic transformations catalyzed by molecular iodine have gained considerable attention due to its low-cost, non-toxic, readily available and environmentally benign nature. A variety of nitrogen heterocycles/bioactive molecules have been synthesized efficiently through this strategy. In addition, this strategy helps to use small tertiary amine molecules as the source of methylene/methyne moieties. Generally, these reactions proceed through iminium ion formation, α-aminoalkyl radical intermediates, metal–complex formation and azomethine ylides. Herein, we have discussed the reactions in a more concise way, giving emphasis to important and novel reactions. Moreover, the mechanisms of all the reactions are well addressed. Undoubtedly, the contents of this review will motivate readers to work towards further novel methodologies in this field.