Used as a highly selective reagent in chemical biology and medicinal chemistry for covalent protein modification. Its strained oxetane ring enhances reactivity, while the sulfonyl fluoride group enables stable bond formation with nucleophilic amino acid residues like lysine and tyrosine. This makes it valuable in developing targeted covalent inhibitors and probes for activity-based protein profiling. The compound’s stability under physiological conditions and selectivity allow for use in live-cell labeling and drug discovery applications. It is also employed in the synthesis of sulfonyl fluoride-containing molecules for use in SuFEx (Sulfur(VI) Fluoride Exchange) click chemistry, enabling rapid and reliable bioconjugation.