chromatography was not required, and an elimination/fluorination sequence readily provided the sulfonyl fluoride reagents. Large scale preparation of PMP OSF derivative 1 on >2 g and OTIPS OSF derivative 2 on >5 g scale was achieved in single runs. Pleasingly the azetidine derivatives proceeded in a similar manner and afforded a series of N-Cbz-ASFs (11-15) through the thiol alkylation-oxidation-elimination/fluorination sequence (Scheme 1a). Cyclobutane derivatives were also prepared through this sequence (16, 17). In each case, the OSF and ASF reagents were stable solids stored at -20 °C for >1 year. OSF 1 and ASF 1 were characterized by X-ray crystallography and displayed comparable conformations. Each of the OSF reagents was demonstrated to react through the unusual deFS pathway to generate amino-oxetanes (see SI for further details). The conditions involve simply warming at 60 °C in acetonitrile in the presence of K2CO3 as base which minimizes the formation of a minor oxetane fluoride side product. Previously we demonstrated that the suitable selection of OSF reagent and amine nucleophile could be applied to the preparation of ten oxetane-analogues of benzamide drugs, with the amino-oxetane providing potential bioisosteric replacement. Here we applied alternative OSF reagents to form directly oxetane analogues of amides (Scheme 1b), including highly chelating nucleophiles that would have been challenging in Lewis acid catalysis and so highlighting the ease and tolerance of these thermal conditions. Isopropyl OSF 3 reacted readily with 2-methylquinolin-8-amine to form an analogue of CDN1163, a SERCA activator of interest for the treatment of diabetic-induced immune dysfunction. Phenoxyarylether OSF 10 reacted similarly with 2picolylamine to form the oxetane analogue of a MAPK14 inhibitor. Oligobenzamides have been applied as a-helix mimetics and show promising potential as anti-cancer agents but often suffer from poor aqueous solubility. 26 JY-1-106 disrupts the Bcl-xL/Bak protein-protein interaction by mimicking the a-helical BH3 domain of Bak. 27 meta-Isopropoxy-containing OSF 5 allowed access to an oxetane analogue of JY-1-106 with increased 3-dimensionality.