Phosphonylation of the lithium anion of phenyl methyl sulfone (I) with diethyl chlorophosphate afforded the sulfonyl phosphonate (II). This was condensed with N-Boc-L-homophenylalaninal (III) under Wadsworth-Emmons conditions to furnish the vinyl sulfone (IV). After acidic Boc group cleavage, the resultant amine (V) was coupled with the N-carbamoyl phenylalanine (VI), via the corresponding mixed anhydride with isobutyl chloroformate, to afford the target amide.