Carbamic acid, N-[(1S)-1-[(2S)-2-oxiranyl]-2-[4-(phenylmethoxy)phenyl]ethyl]-, 1,1-dimethylethyl ester, also known as *erythro*-N-Boc-O-benzyl-L-tyrosine epoxide, is a chiral, non-racemic organic compound. Its structure features a tyrosine-derived backbone with a Boc-protected amine, a benzyl-protected phenolic hydroxyl group, and a terminal (2S)-oxirane (epoxide) ring. This specific stereochemistry (*erythro*, 1S, 2S) is a critical structural attribute. This compound is primarily employed as a key chiral building block and advanced intermediate in pharmaceutical synthesis. The reactive epoxide moiety allows for ring-opening reactions with various nucleophiles, enabling the stereoselective introduction of new functional groups. It is notably used in the research and development of protease inhibitors and other biologically active molecules where the tyrosine-epoxide pharmacophore is essential. As a protected amino acid epoxide, it serves as a versatile synthon for constructing complex peptide mimetics and drug candidates. Its main value lies in providing controlled chirality and reactivity for medicinal chemistry applications, rather than as a bulk commodity or material precursor.