Unlocking SuFEx Reactivity. Extrusion of the anionic SO2F group in the defluorosulfonylation process is dependent primarily on solvent polarity and temperature. Polar solvents (methanol, acetonitrile) effectively stabilize the oxetane carbocation to the extent that a mild rise in temperature promotes the entropically driven loss of SO2. We envisaged that the application of harder nucleophiles, with less polar solvents such as THF would increase the rate of the SuFEx pathway over that of the deFS. Organolithium reagents MeLi and PhLi, were applied in THF at -78 °C, with slow warming to 0 °C to cleanly afford the corresponding oxetane sulfones 93 and 94 (Scheme 3). Interestingly, TMSCF3 reacted rapidly through the SuFEx pathway to afford the CF3-oxetanesulfone (95) even in acetonitrile at 60 °C. Low molecular weight sulfones such as 93 and 95 would have been challenging to obtain by the thiol alkylation from oxetanols since it would require gaseous thiol nucleophiles (e.g. MeSH). Oxetane sulfonamide motifs were accessed through the addition of lithium amide nucleophiles (amine + nBuLi) to a solution of OSF in THF at -78°C to room temperature, producing another previously unknown substitution pattern on oxetanes. Good yields were obtained with secondary amines, benzylamine and anilines (96, 97, 98). Morpholine sulfonamide 96 was characterized by X-ray crystallography. OTIPS OSF 2 reacted without deprotection of the silyl group (99). Reaction with the anion of imidazole, formed with NaH, gave the sulfonyl imidazole, which could be isolated and characterized, including by X-Ray crystallography. Sulfonyl imidazole 100 exhibited poor acidic stability (decomposition observed in CDCl3) with the extrusion of SO2. Treatment with HCl led to the formation of the oxetanol and oxetane chloride through trapping of the oxetane carbocation by residual water or Cl anions.