4-[1-(1-{2-[1-(allylcarbamoyl-hydroxy-methyl)-propylcarbamoyl]-pyrrolidine-1-carbonyl}-2-methyl-propylcarbamoyl)-2-methyl-propylcarbamoyl]-4-(3-tert-butoxycarbonyl-2-tert-butoxycarbonylamino-propionylamino)-butyric acid tert-butyl ester 以71%的产率得到tert-butyl (4S)-5-[[(2S)-1-[[(2S)-1-[(2S)-2-[[(3S)-1,2-dioxo-1-(prop-2-enylamino)pentan-3-yl]carbamoyl]pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-[[(2S)-4-[(2-methylpropan-2-yl)oxy]-2-[(2-methylpropan-2-yl)oxycarbonylamino]-4-oxobutanoyl]amino]-5-oxopentanoate