Used as a chiral auxiliary in asymmetric synthesis, particularly in the preparation of enantiomerically pure sulfonamides and sulfoxides. Its rigid cyclic structure and defined stereochemistry allow for high stereoselectivity in nucleophilic addition and substitution reactions. Commonly employed in pharmaceutical intermediates synthesis where control of stereochemistry is critical, such as in the development of protease inhibitors or other bioactive molecules. The Boc group provides stability and ease of deprotection under mild acidic conditions, making it suitable for multi-step synthetic sequences.