Recent Advances in the Functionalization of Remote C−H Bonds by Hofmann‐Löffler‐Freytag‐type Reactions
Xiaoxu Teng, Tingting Yu, Jianwei Shi, Huisheng Huang, Rentian Wang, Peng Wei, Kai Sun, Shubing Yang, Xin Wang
Abstract
Abstract Nitrogen 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.