Used as a key intermediate in the synthesis of biologically active compounds, particularly in pharmaceutical research. Its spirocyclic structure and functional groups make it valuable for constructing complex heterocycles found in drug candidates. Commonly employed in the development of protease inhibitors and kinase inhibitors due to its ability to mimic peptide bonds and stabilize molecular conformation. Also utilized in solid-phase peptide synthesis and combinatorial chemistry for introducing constrained scaffolds that enhance metabolic stability and target selectivity.