Used extensively in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS) methods. It serves as a protecting group for the cysteine amino acid, ensuring selective reactivity during peptide chain assembly. The Fmoc group is removed under mild basic conditions, while the tBu group is stable and later cleaved under acidic conditions. This compound is crucial for synthesizing peptides with free thiol groups, which are essential for forming disulfide bonds in peptides and proteins. Its application is vital in producing biologically active peptides, such as hormones, enzymes, and therapeutic agents, as well as in research involving protein folding and structure-function studies.