(4R)-4-[(tert-Butoxycarbonyl)amino]-5-(1H-indol-3-yl)pentanoic Acid can be used as reactant/reagent where α/β/γ-peptides represent α-helix-mimetic 12,13-helix foldamers that exhibit enhanced proteolytic stability toward α-chymotrypsin and function as selective inhibitors of p53-hDM2 binding interaction.