Updates on hypervalent-iodine reagents: metal-free functionalisation of alkenes, alkynes and heterocycles.

Hypervalent iodine (HVI) chemistry is a rapidly growing subdomain of contemporary organic chemistry because of its enormous synthetic applications. The high nucleofugality of the phenyliodonio group (-I + Ph) and its radical nature, serving as a single-electron oxidant makes HVI compounds highly valuable in organic synthesis. Due to the feasibility and benignity, reactions that rely solely on HVI reagents as promoters have received particular interest. Considering their great influence and synthetic potential, we contribute a brief synopsis on this field with a specific emphasis on metal-free functionalisations of alkenes, alkynes and heterocycles. The discussion is divided according to the type of substrate and reaction type and elaborated with mechanism and representative examples.