L-Proline t-butyl ester is widely used in organic synthesis, particularly in peptide chemistry, where it serves as a protecting group for the carboxylic acid functionality of L-proline. This protection allows for selective reactions to occur at other sites of the molecule without interference. It is also employed in asymmetric synthesis, aiding in the formation of chiral centers with high enantiomeric purity. Additionally, it finds application in the preparation of pharmaceutical intermediates, where its steric bulk helps control the stereochemistry of the final product. Its stability under various reaction conditions makes it a valuable reagent in complex synthetic pathways.