Fmoc-D-Tyr(3-I)-OH is primarily used in peptide synthesis as a building block for creating custom peptides. Its Fmoc (9-fluorenylmethoxycarbonyl) protecting group allows for selective deprotection during solid-phase peptide synthesis, enabling the stepwise construction of peptide chains. The D-configuration of the tyrosine residue confers resistance to proteolytic enzymes, thereby enhancing the stability of the resulting peptides. The iodine substitution on the tyrosine residue can be utilized in further chemical modifications, such as radioiodination for imaging or therapeutic purposes. This compound is particularly valuable in research involving peptide-based drug development, where specific modifications are required to achieve desired biological activity or targeting properties. Its application extends to studying protein-protein interactions, enzyme activity, and receptor binding, making it a versatile tool in biochemistry and pharmaceutical research.