Widely used in peptide synthesis, this compound serves as a chiral building block for introducing proline-like structures with controlled stereochemistry. Its main application lies in the preparation of modified peptides and peptidomimetics, where the (S)-configuration ensures stereoselective coupling. The Fmoc-protected pyrroline carboxylic acid derivative allows for mild base-labile deprotection during solid-phase synthesis, making it compatible with Fmoc-strategy protocols. It is particularly valuable in the development of pharmaceuticals and bioactive molecules requiring conformationally constrained amino acid residues.