Site-Specific C(sp3)-H Aminations of Imidates and Amidines Enabled by Covalently Tethered Distonic Radical Anions

The utilization of N-centered radicals to synthesize nitrogen-containing compounds has attracted considerable attention recently, due to their powerful reactivities and the concomitant construction of C-N bonds. However, the generation and control of N-centered radicals remain particularly challenging. We report a tethering strategy using SOMO-HOMO-converted distonic radical anions for the site-specific aminations of imidates and amidines with aid of the non-covalent interaction. This reaction features a remarkably broad substrate scope and also enables the late-stage functionalization of bioactive molecules. Furthermore, the reaction mechanism is thoroughly investigated through kinetic studies, Raman spectroscopy, electron paramagnetic resonance spectroscopy, and density functional theory calculations, revealing that the aminations likely involve direct homolytic cleavage of N-H bonds and subsequently controllable 1,5 or 1,6 hydrogen atom transfer.