(3a'S,6'R,7'R,7a'S)-N-methoxy-N-methyl-2-[1'-methyl-2'-oxo-7'-(triethylsilyloxy)hexahydropyrano[4,3-d]oxazol-6'-yl]acetamide

methyl (2S,4R,3a'S,6'R,7'R,7a'S)-4,5-epoxy-2-methoxycarbonylamino-4-[[1'-methyl-2'-oxo-7'-(triethylsilyloxy)hexahydropyrano[4,3-d]oxazol-6'-yl]methyl]pentanoate