(2S,3aR,8aR)-3a-(tert-Butyl-dimethyl-silanyloxy)-2,3,3a,8a-tetrahydro-pyrrolo[2,3-b]indole-1,2,8-tricarboxylic acid 1,8-dibenzyl ester 2-tert-butyl ester

(2S,3aR,8aR)-3a-Hydroxy-1,2,3,3a,8,8a-hexahydro-pyrrolo[2,3-b]indole-2-carboxylic acid tert-butyl ester

(2S,3aR,8aR,2'S,3'aR,8'aR)-3a,3'a-Bis-triethylsilanyloxy-2,3,3a,8a,2',3',3'a,8'a-octahydro-[5,5']bi[pyrrolo[2,3-b]indolyl]-1,2,8,1',2',8'-hexacarboxylic acid 1,8,1',8'-tetrabenzyl ester 2,2'-di-tert-butyl ester