In Situ Generation and Reactivity of Fluorosulfonimidoyl Azide (R-N═SOFN3): Expanding the Scope of SOF4-Based SuFEx Chemistry

Abstract

Here, we report the use of iminosulfur oxydifluorides, derived from SOF₄ and primary amines, for the generation of the unprecedented aza-analogues of fluorosulfury azide (FSO₂N₃), namely, fluorosulfonimidoyl azide (R-N═SOFN₃). Unlike FSO₂N₃, R-N═SOFN₃ acts as a sulfamoyl nitrene precursor, undergoing imidation with sulfoxides and thioethers to from products featuring unique “-N = S(VI)F–N = S(VI)-” linkages without metal catalyst. The fluoride at the S(VI) center can be sequentially exchanged to generate diverse three-deminsional structures with tunable SuFEx reactivity. Mechanistic studies reveal that R-N = SOFN₃ decomposes to the sulfamoyl nitrene intermediate, which is stabilized by the adjacent “-S(VI)=N-” nitrogen atom. This facilitates the formation of three-membered rings that react further with S(IV)/S(II). These novel transformations expand the scope of SOF₄-based SuFEx chemistry, demonstrating that R-N = SOFN₃ enables dual reactivity through both nitrene-driven and tunable SuFEx-based linkages.