Used in the synthesis of antiviral agents, specifically as a key intermediate in the production of non-nucleoside NS5A inhibitors for the treatment of hepatitis C virus (HCV) infections, such as ledipasvir. The compound features a protected 7H-pyrrolo[2,3-d]pyrimidin-4-yl core linked to a 1H-pyrazol-1-yl group and a cyclopentyl propanenitrile moiety, with a SEM (2-(trimethylsilyl)ethoxy)methyl protecting group on the pyrrole nitrogen. It is provided as the (2S,3S)-2,3-bis(benzoyloxy)succinate salt to ensure the (S) stereochemistry at the chiral center. This intermediate enables selective deprotection and coupling in multi-step synthetic routes, valuable in medicinal chemistry for developing drug candidates with enhanced potency, metabolic stability, and pharmacokinetic profiles.