Used in peptide synthesis as a protected form of aspartic acid. The Fmoc group ensures selective deprotection during solid-phase peptide synthesis, while the OAll (allyl ester) protects the side chain carboxyl group. This allows precise control over the assembly of peptide chains, particularly in complex sequences. It is commonly employed in the production of pharmaceuticals, bioactive peptides, and research applications where specific amino acid sequences are required. The allyl group can be removed under mild conditions, minimizing damage to the peptide structure.