Used in peptide synthesis as a protecting group for glutamic acid, ensuring selective reactions during the assembly of peptide chains. It is particularly valuable in solid-phase peptide synthesis (SPPS) where the Fmoc group provides temporary protection, while the tBu group safeguards the side chain carboxyl group. This compound facilitates the efficient and precise construction of complex peptides, making it essential in the development of pharmaceuticals, bioactive peptides, and research applications. Its stability and ease of removal under mild conditions make it a preferred choice in modern peptide chemistry.