The Hofmann degradation of dipeptide amide (I) using bis(trifluoroacetoxy)iodobenzene in aqueous acetonitrile yielded the geminal diamine derivative (II). After deprotection of the tert-butyl group of (II) with aqueous trifluoroacetic acid containig anisole, the resulting aminoalcohol (III) was coupled with N-(benzyloxycarbonyl) tetrahydroisoquinoline-3-carboxylic acid (IV) by means of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-HCl (EDC) and 1-hydroxy- benzotriazole (HOBt) to afford the geminal diamide (V). The catalytic hydrogenolysis of both benzyloxycarbonyl groups of (V) was carried out in the presence of Pd/C, and the deprotected diamino compound (VI) was finally converted to the bis(Fmoc) derivative by coupling with N-(9-fluorenylmethoxycarbonyloxy)succinimide (VII) in the presence of N-methylmorpholine.