Used in the synthesis of varenicline, a medication for smoking cessation. It serves as a key chiral intermediate in pharmaceutical manufacturing, enabling the production of the active ingredient with high enantiomeric purity. The compound's structure allows for selective chemical transformations critical to forming varenicline’s bicyclic framework. Its hydrochloride salt form improves stability and handling during synthesis. Widely utilized in multi-step routes to ensure yield efficiency and stereochemical control.