(-)-ethyl 8-[(3S,9S,14aR)-9-benzyl-6,6-dimethyl-1,4,7,10-tetraoxotetradecahydropyrrolo[1,2-a][1,4,7,10]tetra-azacyclododecin-3-yl]-3-oxooctanoate

S-7-((3S,9S,14aR)-9-benzyl-6,6-dimethyl-1,4,7,10-tetraoxotetradecahydropyrrolo[1,2-a][1,4,7,10]tetraazacyclododecin-3-yl)-2-oxoheptyl O-ethyl carbonodithioate

benzyl 6-[(3S,9S,14aR)-9-benzyl-6,6-dimethyl-1,4,7,10-tetraoxotetradecahydropyrrolo[1,2-a][1,4,7,10]tetraazacyclododecin-3-yl]-4-(ethoxycarbonothioylthio)hexanoate

S-(R)-1-[(3S,9S,14aR)-9-benzyl-6,6-dimethyl-1,4,7,10-tetraoxotetradecahydropyrrolo[1,2-a][1,4,7,10]tetraazacyclododecin-3-yl]-7-(tert-butyldimethylsilyloxy)-6-oxooctan-3-yl O-ethyl carbonodithioate

S-(S)-1-[(3S,9S,14aR)-9-benzyl-6,6-dimethyl-1,4,7,10-tetraoxotetradecahydropyrrolo[1,2-a][1,4,7,10]tetraazacyclododecin-3-yl]-7-(tert-butyldimethylsilyloxy)-6-oxooctan-3-yl O-ethyl carbonodithioate