© 2020 The Japan Institute of Heterocyclic Chemistry – The first synthesis of optically active β-arginine was achieved starting from commercially available pyroglutamic acid. The new synthetic protocol is characterized by the use of nitrile as a carboxylic acid surrogate which could be transformed to the corresponding 2-acyl-1,3-bis(1,1-dimethylethyl)imidodi-carbonic acid ester (active amide) via Pt-catalyzed hydration under the mild conditions. The active amide was converted to β-arginine and Boc-β-Arg-Val-OMe in good yield.