(3R,5S)-5-{2-[(S)-3-(tert-butyldimethylsilanyloxy)-2-(4-methoxybenzyloxy)propyl]thiazol-4-yl}-3-(2,2,2-trichloro-1,1-dimethylethoxycarbonylamino)hexanoic acid (E)-(S)-4-iodo-1,3-dimethylbut-3-enyl ester