L-Valine t-butyl ester hydrochloride is primarily used in peptide synthesis as a protecting group for the amino acid valine. The t-butyl ester group helps to shield the carboxyl group during the reaction process, preventing unwanted side reactions. This compound is particularly valuable in solid-phase peptide synthesis, where it allows for the stepwise construction of peptides with high precision. Additionally, it is employed in the preparation of complex organic molecules, where selective protection and deprotection of functional groups are required. Its stability and ease of removal under mild acidic conditions make it a preferred choice in synthetic organic chemistry.