Used as a chiral building block in pharmaceutical synthesis, particularly in the development of active pharmaceutical ingredients (APIs) requiring high enantiomeric purity. The oxetane ring offers metabolic stability and improved physicochemical properties in drug candidates. Commonly employed in the preparation of protease inhibitors and kinase inhibitors due to its ability to mimic structural motifs in biologically active molecules. The tosylate group facilitates salt formation and enhances crystallinity, aiding in purification and isolation during multi-step syntheses. Also utilized in the manufacture of certain antiviral and anticancer agents where stereochemistry plays a critical role in efficacy.