Used in peptide synthesis as a protected building block, particularly for introducing tyrosine residues in a controlled manner. The Boc group protects the amine, while the tert-butyl ester protects the carboxylic acid, allowing selective deprotection and coupling in stepwise solid-phase or solution-phase synthesis. Commonly applied in the preparation of complex peptides and proteins where orthogonal protection strategies are required. Also utilized in the synthesis of bioactive molecules, including hormones and enzyme inhibitors, due to its stability under various reaction conditions and compatibility with other protecting groups.