(R)-3-((tert-Butoxycarbonyl)amino)-3-(2,4-dichlorophenyl)propanoic acid is a chiral amino acid derivative featuring a Boc-protected amino group and a carboxylic acid functional group attached to a stereogenic center bearing a 2,4-dichlorophenyl substituent. This compound serves as a crucial chiral building block in pharmaceutical synthesis. Its primary and well-documented application is as a key intermediate in the synthesis of novel antifungal agents, particularly echinocandin-class compounds. Research indicates its use in the preparation of advanced intermediates for caspofungin acetate, a potent antifungal medication used to treat invasive aspergillosis and candidiasis. The (R)-configuration at the beta-amino acid center is essential for the biological activity of the final drug molecule. The presence of both a protected amine and a carboxylic acid allows for selective coupling and further elaboration, making it a versatile synthon for constructing complex peptide-like structures in medicinal chemistry programs targeting infectious diseases.