N-Cbz-L-threonine benzyl ester is primarily used in peptide synthesis as a protected form of threonine. The Cbz (carbobenzoxy) group acts as a protective group for the amino functionality, while the benzyl ester protects the carboxyl group. This dual protection allows for selective deprotection during the synthesis of complex peptides, ensuring that the threonine residue is incorporated accurately without unwanted side reactions. It is particularly valuable in solid-phase peptide synthesis (SPPS) and solution-phase peptide synthesis, where precise control over the sequence and structure of peptides is essential. Additionally, it finds applications in the preparation of peptide-based pharmaceuticals, bioactive peptides, and research compounds where threonine plays a critical role in the biological activity of the final product.