Intramolecular C(sp₃)-H Bond Amination Strategies for the Synthesis of Saturated N-containing Heterocycles

Chimia (Aarau). 2020 Nov 25;74(11):895-903. doi: 10.2533/chimia.2020.895.

Abstract

The selective functionalization of C(sp³)-H bonds via intramolecular amination reactions represents a very attractive strategy for the construction of saturated N-containing heterocycles (SNHets). Over the past de- cades, the chemical community has devoted its efforts towards expanding the synthetic toolbox with the aim of facilitating access to these key fragments in a controllable, reproducible and efficient manner. This review covers selected examples of the most recent advances in intramolecular C(sp³)-N bond-forming reactions by three main approaches: (1) the Hofmann-Löffler-Freytag (HLF) reaction; (2) transition-metal-catalyzed nitrene C(sp³)-H inser- tion; and (3) transition-metal-catalyzed ligand-assisted C(sp³)-N bond-forming reactions via a reductive elimination step. We will discuss reactivity, selectivity and the major mechanistic insights into these transformations.