Tert-Butyl (2S,4R)-4-amino-2-(methoxymethyl)pyrrolidine-1-carboxylate is a chiral pyrrolidine derivative featuring both a Boc-protected amine and a free primary amine at the 4-position, along with a methoxymethyl substituent at the 2-position. This specific stereochemistry ((2S,4R)) is crucial for its intended applications. This compound is a key chiral building block and advanced intermediate in pharmaceutical research and development. Its primary application is in the synthesis of complex drug candidates, particularly those targeting viral infections. It serves as a critical precursor for the synthesis of potent protease inhibitors, such as certain anti-Hepatitis C Virus (HCV) agents like Glecaprevir. The stereodefined structure and functional groups are essential for achieving the desired biological activity and binding affinity of the final active pharmaceutical ingredient (API). As a high-value synthetic intermediate, it is typically used in the later stages of complex multi-step syntheses. Its availability as a well-defined chiral scaffold accelerates medicinal chemistry efforts by providing a ready-to-use fragment with the correct absolute configuration, thereby avoiding lengthy asymmetric synthesis routes.