Diethyl-carbamic acid 1-(tert-butyl-dimethyl-silanyl)-1H-indol-5-yl ester (9.26 g, 26.7 mmol) is dissolved in THF (250 mL), flushed with nitrogen and cooled to −78° C. TMEDA (5 mL, 33.1 mmol) is then added followed by sec-butyllithium (24.8 mL, 34.7 mmol) and the reaction is stirred for 30 minutes. Hexachloroethane (12.73 g, 53.8 mmol) in 50 mL of THF is added over 10 minutes to the reaction. The reaction is allowed to warm to room temperature overnight (15 hours). The reaction is cooled using an ice bath and a saturated ammonium chloride (aq) solution is added (150 mL). The mixture is then extracted with ethyl acetate, dried (sodium sulfate) and concentrated to obtain the title compound as an oil that is used without further purification. MS (ESI) m/z 381.1 (M+1).
