(2S,3R)-3-(4-benzyloxy-3-{(R)-1-[(S)-((R)-2-benzyloxycarbonylamino-3-methylbutyrylamino)-(tert-butoxycarbonylmethylcarbamoy)methyl]-1-methylprop-2-ynyloxy}phenyl)-2-(tert-butoxycarbonylmethylamino)-3-hydroxypropionic acid benzyl ester