Switchable Amination Pathways of Chromones via Iodonium Salt/Amine Modulation

Iodonium salts have shown great potential as metal-free reagents in various transformations, offering a promising alternative to transition-metal-catalyzed arene amination. Herein, we report the design and synthesis of chromone-based iodonium salts (CMISs) and demonstrate their efficiency in selective chromone amination. Unlike the conventional ligand exchange/coupling pathway, mechanistic studies reveal a unique amination pathway specific to the chromone scaffold, in which the aryliodonium unit simultaneously facilitates N-Michael addition and the formation of a newfound chromone-derived strained alkyne intermediate, leading to mechanistic competition while directing product configuration. By further modulating the basicity and steric hindrance of amines, three distinct classes of aminated products ((Z)-2-(aminomethylene)-benzofuranones, β-aminochromones and α-aminochromones) were accessed.