Used as a chiral building block in the synthesis of pharmaceuticals, particularly in the development of active pharmaceutical ingredients (APIs) requiring high enantiomeric purity. Its protected pyrrolidine structure with a reactive chloromethyl group allows for selective functionalization, making it valuable in constructing complex molecules such as neurokinin antagonists, antiviral agents, and other bioactive compounds. Commonly employed in medicinal chemistry for structure-activity relationship (SAR) studies due to its rigid framework and stereochemical control.