(2S,4R)-4-(tert-Butyl-dimethyl-silanyloxy)-2-((R)-1-hydroxy-but-3-enyl)-pyrrolidine-1-carboxylic acid benzyl ester

(2S,4R)-4-(tert-Butyl-dimethyl-silanyloxy)-2-[(R)-2-[(R)-1-((S)-1-carboxy-ethyl)-octyloxycarbonyl]-1-(4-methoxy-benzyloxy)-ethyl]-pyrrolidine-1-carboxylic acid benzyl ester