Used in peptide synthesis as a protected chiral building block, particularly in the preparation of modified amino acids and bioactive peptides. The cyano group allows for further functionalization, such as conversion to tetrazole rings or carboxylic acids, enabling the design of peptidomimetics and enzyme inhibitors. The Fmoc group provides orthogonal protection for the amine, making it compatible with solid-phase synthesis under mild basic conditions. Its stereochemistry is essential for constructing stereoselective peptide structures with desired biological activity.