合成路线1

The reaction of N-Boc-L-serine (I) with 2-fluoronitrobenzene (II) by means of NaH in DMF gives N-Boc-O-(2-nitrophenyl)-L-serine (III), which is reduced with H2 over Pd/C in methanol yielding the 2-aminophenyl derivative (IV). The cyclization of (IV) by means of EDAC in DMF affords the benzoxazepinone (V), which is condensed with benzyl 2-bromoacetate (VI) by means of LHMDS in THF providing the benzoxazepinone acetic ester (VII). The deprotection of the carbamate group of (VII) with HCl in dioxane affords (VIII) with a free amino group that is condensed with 2-benzyl-3-[N-(benzyloxy)-N-formylamino]propionic acid (IX) by means of EDAC in dichloromethane giving the corresponding amide (X). The deprotection of the benzyl groups of (X) with H2 over Pd/C in methanol yields the expected mixture of diastereomers that is resolved by preparative HPLC to afford the target compound.