NaI (2.04 g, 14 mmol) in acetone (10 mL) was added dropwise to a stirred solution of N-chlorosuccinimide (1.83 g, 14 mmol) in acetone (10 mL) protected from light. After 15 min, a solution of 5-(4-trifluoromethylphenyl)indole-2-carboxylic acid ethyl ester (3.80 g, 11 mmol; see step (a) above) in acetone (60 mL) was added dropwise, followed by stirring for 2 h at rt. The mixture was poured into Na2S2O3 (aq, 10%, 250 mL) and extracted with EtOAc (200 mL). The combined extracts were washed with NaHCO3 (aq, sat), water and brine, dried (Na2SO4) and concentrated. The residue was treated with petroleum ether to give the sub-title compound. Yield 4.88 g (93%).
