Direct selective azidation of C(sp3)−H groups

Organic azides are convenient and versatile intermediates for the synthesis of various nitrogen-containing scaffolds, including biologically active compounds, approved drugs, functional materials, etc. Designing general approaches to deliberately chemo-, regio-, and steroselective synthesis of aliphatic azides is an urgent task of synthetic chemistry. Particularly challenging is direct azidation of non-activated C(sp³)−H groups, capable of providing ready access to remote and late-stage functionalization of complex targets without need for re-designing existing multistep synthetic procedures. This contribution surveys the C(sp³)−H azidation approaches known to date, both non-catalytic and catalytic, including enzyme-mediated ones, with the major focus on the synthetic perspective of these transformations. Essential mechanistic details are briefly discussed.