Used in peptide synthesis as a protected building block, particularly for introducing aspartic acid residues in a controlled manner. The Boc group protects the alpha-amino function, while the methyl ester masks the side chain carboxylic acid, allowing selective coupling at the C-terminus. Commonly applied in the preparation of complex peptides and pharmaceutical intermediates where orthogonal protection strategies are required. Its stability under various reaction conditions makes it suitable for stepwise solid-phase and solution-phase peptide assembly. Also utilized in the synthesis of enzyme inhibitors and bioactive molecules involving aspartate-containing sequences.