Used as a key chiral intermediate in the synthesis of potent antiviral agents, particularly in the development of hepatitis C virus (HCV) NS5A inhibitors. Its rigid oxazinone scaffold with defined stereochemistry enables high selectivity and binding affinity in drug candidates. It is valued in medicinal chemistry for improving metabolic stability and pharmacokinetic properties in final drug formulations. Commonly employed in structure-activity relationship (SAR) studies to optimize antiviral potency and reduce off-target effects.