1-Pyrrolidinecarboxylic acid,2-[(1S,2S)-3-(3,5-difluorophenyl)-1-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-[[(phenylmethoxy)carbonyl]amino]propyl]-4-hydroxy-,1,1-dimethylethyl ester, (2R,4R)-