Used in solid-phase peptide synthesis, this compound serves as a protected amino acid building block, enabling selective deprotection of the epsilon-amino group of lysine while keeping the alpha-amino group masked. The Dde group allows for orthogonal protection strategies, as it can be removed selectively with hydrazine under mild conditions without affecting other common protecting groups like Fmoc. This feature is particularly valuable in the synthesis of branched peptides, peptide conjugates, and cyclic structures where site-specific modifications are required. Its D-configuration makes it suitable for designing metabolically stable peptides or probing stereochemical effects in structure-activity relationship studies.