Methyl (S)-2-((tert-butoxycarbonyl)amino)-2-cyclopropylacetate is a chiral amino acid derivative used in organic synthesis, particularly in the preparation of peptides and other complex molecules. The (S) indicates the stereochemistry of the molecule, denoting that it is the (S)-enantiomer. The tert-butoxycarbonyl (Boc) group serves as a protective group for the amino group, preventing unwanted reactions during synthesis. The cyclopropylacetate moiety provides a cyclopropyl group, adding rigidity and unique steric properties to the molecule. The methyl ester at the end can be used in further reactions or as a protective group for the carboxyl group. This compound is valuable for introducing specific stereochemistry and structural features into synthetic molecules.