Fmoc-DL-alanine is a derivative of the amino acid alanine, where the amino group is protected by a 9-fluorenylmethoxycarbonyl (Fmoc) group. It is a racemic mixture (DL-form) of the compound. The Fmoc group is a cornerstone in modern solid-phase peptide synthesis (SPPS), serving as a base-labile protecting group for the α-amino function. Its primary and most significant application is as a key building block in the automated synthesis of peptides and peptidomimetics, particularly using the Fmoc-SPPS strategy. It is used to incorporate alanine residues into peptide chains. The Fmoc-protected amino acid is coupled to the growing peptide chain on a resin, and the Fmoc group can be selectively removed under mild basic conditions (e.g., piperidine) to allow for the next coupling cycle. This makes it an essential reagent in pharmaceutical research, biochemistry, and the development of therapeutic peptides. While its core use is in peptide synthesis, it also serves as a versatile chiral synthon in general organic synthesis due to its protected amino acid structure. It is commercially available from numerous suppliers specializing in peptide synthesis reagents and fine chemicals.