Sulfur(iv) reagents for the SuFEx-based synthesis of substituted sulfamate esters

Abstract

Sulfur(VI) fluoride exchange chemistry has been reported to be effective at synthesizing valuable sulfur(VI) functionalities through sequential nucleophilic additions, yet oxygen-based nucleophiles are limited in this approach to phenolic derivatives. Herein, we report a new sulfur(IV) fluoride exchange strategy to access synthetically challenging substituted sulfamate esters from alkyl alcohols and amines. We also report the development of a non-gaseous, sulfur(IV) fluoride exchange reagent, N-methylimidazolium sulfinyl fluoride hexafluorophosphate (MISF). By leveraging the reactivity of the sulfur(IV) center of this novel reagent, the sequential addition of alcohols and amines to MISF followed by oxidation afforded the desired substituted sulfamates in 40–83% yields after two steps. This new strategy expands the scope of SuFEx chemistry by increasing the accessibility of underdeveloped –S(O)F intermediates for future explorations.