(9H-fluoren-9-yl)methyl (2R,2'S,4R,9a'S)-2'-isobutyl-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

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

(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'-isobutyl-3',5-dioxo-2',3',4,5-tetrahydro-3H-spiro[furan-2,9'-imidazo[1,2-a]indole]-1'(9a'H)-carboxylate

(2S,9R,9aS)-9-Hydroxy-2-isobutyl-9-[(R)-2-methoxycarbonyl-2-(2,2,2-trichloro-ethoxycarbonylamino)-ethyl]-3-oxo-2,3,9,9a-tetrahydro-imidazo[1,2-a]indole-1-carboxylic acid benzyl ester

benzyl (2R,2'S,4R,9a'S)-2'-isobutyl-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