Recently, we introduced a unique defluorosulfonylative (deFS) coupling process of oxetane sulfonyl fluorides OSFs with neutral amine nucleophiles. Sulfonyl fluorides typically react with nucleophiles in Sulfur-Fluoride Exchange (SuFEx) reactions to yield S(VI) derivatives such as sulfonamides and sulfonate esters. In contrast to sulfonyl chlorides, sulfonyl fluorides are notably more stable and can persist intact through further reactions. The combination of high stability with selective activation 22 has made the sulfonyl fluoride functional group ideal for applications in drug discovery and chemical biology 23 and was coined a 'click reagent' by Sharpless in an influential report in 2014. 3-Aryloxetane-3-sulfonyl fluorides did not show the expected SuFEx reactivity. Instead, these reagents underwent selective defluorosulfonylation (deFS) upon mild thermal activation (60 °C) to generate oxetane carbocations that were trapped with a variety of amine nucleophiles to yield amino-oxetanes as potential isosteres of amides. Amine libraries were directly coupled and the deFS reaction demonstrated high functional group tolerance.