dimethyl (3aS,5aR,5'S,7R,8aR,8bR)-1-methyl-2,2'-dioxooctahydrospiro[furo[2',3':5,6]pyrano[4,3-d]oxazole-7,3'-pyrrolidine]-1',5'-dicarboxylate

methyl (2S,4S,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

methyl (2S,3a'S,5a'R,7'R,8aS,8bS)-3-[7'-hydroxymethyl-1'-methyl-2'-oxooctahydro-3',5',8'-trioxa-1'-aza-as-indacen-7'-yl]-2-(methoxycarbonylamino)propionate