Used in peptide synthesis as a protected chiral building block, particularly for incorporating methionine-like structures with controlled stereochemistry. The Fmoc group allows for mild base-labile protection compatible with solid-phase synthesis, making it suitable for preparing structured peptides in pharmaceutical and biochemical research. The methylsulfonyl moiety adds polarity and can influence peptide conformation or binding properties. Commonly applied in the development of enzyme inhibitors or bioactive peptides where precise side-chain functionality and stereochemistry are critical.