Chemoselective Intramolecular Functionalization of Methyl Groups in Nonconstrained Molecules Promoted by N‑Iodosulfonamides

Mechanistic evidence observed in Hofmann–Löffler–Freytag-type reactions has been crucial to achieve the chemoselective functionalization of methyl groups under mild conditions. Radical-mediated methyl iodination and subsequent oxidative deiodination are the key steps in this functionalization, where iodine chemistry has a pivotal role on the formation of the C–N bond. The concepts of single hydrogen atom transfer (SHAT) and multiple hydrogen atom transfer (MHAT) are introduced to describe the observed chemoselectivity.