(9H-fluoren-9-yl)methyl (2R,2'S,4R,9a'S)-4-(2-((R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(phenylselanyl)propanamido)benzamido)-2'-methyl-3',5-dioxo-2',3',4,5-tetrahydro-3H-spiro[furan-2,9'-imidazo[1,2-a]indole]-1'(9a'H)-carboxylate

2,2,2-trichloroethyl ((2S,2'S,4R,9a'S)-2'-methyl-3',5-dioxo-1',2',3',4,5,9a'-hexahydro-3H-spiro[furan-2,9'-imidazo[1,2-a]indol]-4-yl)carbamate

(R)-3-((2S,9S,9aS)-9-Hydroxy-2-methyl-3-oxo-2,3,9,9a-tetrahydro-1H-imidazo[1,2-a]indol-9-yl)-2-(2,2,2-trichloro-ethoxycarbonylamino)-propionic acid methyl ester

(S)-9-[(R)-2-(2-Amino-benzoylamino)-2-methoxycarbonyl-ethyl]-2-methyl-3-oxo-2,3-dihydro-imidazo[1,2-a]indole-1-carboxylic acid benzyl ester

benzyl (2S,2'S,4R,9a'R)-9a'-methoxy-2'-methyl-3',5-dioxo-4-(((2,2,2-trichloroethoxy)carbonyl)amino)-2',3',4,5-tetrahydro-3H-spiro[furan-2,9'-imidazo[1,2-a]indole]-1'(9a'H)-carboxylate