(S)-(-)-4-tert-Butoxy-2,5-oxazolidinedione is a chiral heterocyclic compound featuring an oxazolidinedione core structure with a tert-butoxy substituent at the 4-position. It is a white to off-white crystalline solid. This compound is a key chiral building block and intermediate in organic synthesis. Its primary and most significant application is in the pharmaceutical industry for the synthesis of chiral active pharmaceutical ingredients (APIs). Specifically, it serves as a crucial intermediate in the production of β-lactam antibiotics, such as certain carbapenems and penems. The chiral oxazolidinedione scaffold provides a versatile platform for constructing complex molecules with defined stereochemistry, which is essential for biological activity. As a chiral synthon, it is valued for its ability to introduce stereocenters and functional groups in a controlled manner during multi-step synthetic routes targeting bioactive molecules.