Heteroarylation of Functionalized Alkenes via Hexafluoroisopropanol-Assisted Redox Activation of Areneazo-2-(2-nitro)propanes.

The hexafluoroisopropanol (HFIP)-assisted thermal denitrogenative fragmentation of areneazo-2-(2-nitro)propanes enabled heteroarylation of functionalized alkenes through cooperative radical and redox processes. Bench-stable areneazo-2-(2-nitro)propanes served as versatile aryl radical precursors for carboheterocyclization with alkenyl esters, affording diverse arylated lactones and heterocycles with broad functional group tolerance. Mechanistically, the radical fragmentation-nitro-nitrite isomerization of areneazo-2-(2-nitro)propanes generated nitric oxide that underwent a redox process with tertiary radical intermediates to promote heterocyclization. The oxidant-free conditions generated dinitrogen and acetone as benign byproducts.