Ammonium Chloride → 7-[(Ethylsulfanyl)methyl]-1H-indole

A solution of 7.40 g (37.5 mmol) of the compound from Example 3A in 195 ml of tetrahydrofuran was added dropwise to 134 ml (93.8 mmol) of a 0.7N solution of vinylmagnesium bromide in tetrahydrofuran under argon at −78° C., and the mixture was stirred at −78° C. for 2 h. The reaction mixture was then slowly added to an ice-cold, saturated aqueous ammonium chloride solution and extracted three times with ethyl acetate. The combined organic phases were washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered and concentrated. The residue was purified by flash chromatography (mobile phase: cyclohexane/ethyl acetate 9/1) to result in 4.98 g (69% of theory) of the title compound.