(S)-2-Amino-2-(3-fluoro-5-methoxyphenyl)acetic acid is a chiral amino acid derivative. The (S) indicates the stereochemistry at the chiral center. This compound consists of an amino group attached to the alpha carbon, which is also connected to a substituted phenyl ring bearing a fluoro group at the 3-position and a methoxy group at the 5-position. The presence of these functional groups adds both electronic and steric effects, which can influence the reactivity and interactions of the molecule. This derivative is used in peptide synthesis and medicinal chemistry to introduce specific aromatic and electronic properties into peptides or other bioactive molecules.