Used in pharmaceutical synthesis as a protected building block for drug development, particularly in the preparation of bioactive molecules and central nervous system agents. The Boc-protected pyrrolidine ring with an ethynyl group allows for selective transformations, including coupling reactions via the alkyne functionality, such as click chemistry or Sonogashira reactions. Commonly employed in medicinal chemistry for constructing peptidomimetics and heterocyclic compounds. Its structure supports conformational restriction, enhancing selectivity and metabolic stability in final drug candidates.