Recent Advances in the Functionalization of Remote C−H Bonds by Hofmann‐Löffler‐Freytag‐type Reactions

AbstractNitrogen radicals are one of the most useful reactive intermediates for selective transposition via intramolecular hydrogen atom transfer (HAT). The Hofmann‐Löffler‐Freytag (HLF) reaction is a distinctive radical‐based approach in which nitrogen radicals are used for remote C−H bond functionalization via intramolecular HAT. Due to its excellent regioselectivity and atomic economy, the HLF reaction represents a new approach for the preparation of valuable functional molecules. In this review, we provide a brief overview of recent research advances in remote C−H bond functionalization via nitrogen radicals mediated HLF‐type reactions involving intermolecular cyclization, intramolecular cyclization, and remote δ‐site functionalization.