Used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS), where it serves as a protected form of D-aspartic acid. The Fmoc group provides protection for the amino group during the synthesis process, while the allyl ester protects the carboxyl group. This allows for selective deprotection and coupling of amino acids, enabling the construction of complex peptides with high precision. It is especially valuable in synthesizing peptides with specific chirality or sequences, making it essential in pharmaceutical research, drug development, and the study of protein interactions.