(S)-Methyl 2-aminopent-4-ynoate hydrochloride is a chiral, non-proteinogenic amino acid derivative. It features a propargyl side chain and an ester-protected carboxylic acid group, making it a versatile building block. The compound is supplied as a hydrochloride salt to enhance its stability and handling properties. This compound is primarily utilized as a key chiral intermediate in pharmaceutical research and development. Its propargyl functionality allows for participation in click chemistry reactions, such as copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling the efficient construction of complex molecular architectures. It serves as a crucial precursor in the synthesis of various biologically active molecules, including potential drug candidates targeting neurological disorders and other therapeutic areas. As a chiral synthon containing both an amine and an alkyne group, it is a valuable reagent for medicinal chemists to introduce specific structural motifs and stereochemistry into target compounds. Its application extends to the synthesis of peptidomimetics and other constrained scaffolds.