13-(tert-butyl) 1-methyl (4R,4aR,7S,13bR,14aR)-7-(((tert-butoxycarbonyl)oxy)methyl)-2-hydroxy-4-methyl-5-oxo-4a-(phenylsulfonyl)-3,4a,5,7,8,13b,14,14a-octahydroindolo[2',3':3,4]pyrido[1,2-b]isoquinoline-1,13(4H)-dicarboxylate

((2R,12bR)-4-Oxo-1,2,3,4,6,7,12,12b-octahydro-indolo[2,3-a]quinolizin-2-yl)-acetic acid methyl ester

(2R,12bR)-2-Methoxycarbonylmethyl-4-oxo-1,3,4,6,7,12b-hexahydro-2H-indolo[2,3-a]quinolizine-12-carboxylic acid tert-butyl ester