Fmoc-D-Dap(ivDde)-OH is a protected derivative of D-diaminopropionic acid (D-Dap) used primarily in solid-phase peptide synthesis (SPPS). The Fmoc group protects the α-amino group, allowing removal with bases such as piperidine, while the orthogonal ivDde group protects the side-chain amino group, enabling selective deprotection with hydrazine. This dual protection strategy ensures precise control over reactions during peptide chain assembly, preventing unwanted side reactions and facilitating the construction of complex peptides with multiple functional groups. It is particularly valuable in the synthesis of therapeutic peptides, peptide hormones, and other biologically active compounds for research and pharmaceutical applications.