Used as a chiral building block in the synthesis of pharmaceuticals, particularly in the development of active pharmaceutical ingredients (APIs) requiring stereochemical control. Its aldehyde functionality allows for further derivatization through reactions such as reductive amination or nucleophilic addition, enabling the construction of complex nitrogen-containing heterocycles. Commonly employed in medicinal chemistry for the preparation of protease inhibitors, receptor agonists, and other bioactive molecules where the (S)-configuration is critical for biological activity. The tert-butyl carbamate (Boc) group provides stability and acts as a protecting group during multi-step syntheses, allowing selective deprotection under mild acidic conditions.