A mixture of 7-chloro-2,3,5,10,11,11c-hexahydro-1H-indolizino[7,6-b]indole and 10-chloro-2,3,5,6,7,11c-hexahydro-1H-indolizino[7,8-b]indole (non-separable regioisomers, 500 mg, 2.03 mmol, 1 equiv) and 1-(2-bromoethyl)-4-fluorobenzene (577 mg, 2.84 mmol, 1.4 equiv) were heated at 95° C. with triethyl amine (0.85 mL, 6.09 mmol, 3 equiv) in 6 mL of EtOH for 18 h. The mixture was brought to RT followed by dilution with EtOAc (40 mL), washed with water (2×10 mL), and once with brine, then dried over sodium sulfate and evaporated under reduced pressure. The crude product was purified by column chromatography over 230-400-mesh silica gel using a gradient of MeOH in EtOAc (0 to 50%). The product was further purified by reverse phase HPLC. Column: ZORBAX SB C18, 4.6×250 mm, 5μ, retention time (min): 9.71, purity: 95.20%;
