Used in organic synthesis as a chiral auxiliary and building block for pharmaceuticals. It plays a key role in asymmetric synthesis, helping control stereochemistry in complex molecule construction. Commonly applied in the development of active pharmaceutical ingredients (APIs) where stereoselectivity is critical. Its structure allows for ring-opening reactions with nucleophiles such as amines or alcohols, forming chiral intermediates used in drug manufacturing. Also employed in the preparation of biodegradable polymers and specialty esters due to its reactive anhydride group and aromatic backbone.