Coupling of Fmoc-D-arginine(PMC) (I) with phenylalaninol methyl ether (II) in the presence of EDC and HOBt provided amide (III). Cleavage of the Fmoc group by using piperidine in DMF afforded amine (IV), which was subsequently coupled with dinaphthylpropionic acid (V), yielding diamide (VI). The pentamethylchromansulfonyl protecting group (PMC) was finally removed by treatment with trifluoroacetic acid in the presence of ethanedithiol and anisole.