4-Bromo-1-(phenylsulfonyl)-1H-indol-5-yl acetate (Intermediate 22, 0.57 g, 1.5 mmol) was dissolved in toluene (10 mL) under an atmosphere of N2 gas and 1-ethoxyvinyl-tributylstannane (0.78 g, 2.2 mmol) and bis-(triphenylphosphin)-palladium(II)-chloride (50.8 mg, 0.072 mmol) were added and the mixture was heated at 110° C. After 30 minutes additional catalyst (25 mg, 0.036 mmol) was added and the mixture was heated at 110° C. for an additional 3 hours, cooled and filtered through a plug of silica gel using EtOAc as the eluent. The filtrate was washed with 1 M HCl and saturated aqueous brine, dried over (MgSO4) and evaporated. The crude product was dissolved in THF/1 M HCl 2:1 (40 mL) and stirred for 30 minutes at room temperature. The mixture was evaporated and partitioned between water and DCM. The organic phase was dried (MgSO4) and evaporated. The crude material was purified by flash chromatography on silica gel using 10% petroleum ether in DCM as the eluent to give the title compound (100 mg) as a light yellow solid. MS m/z 316 [M+H]+.
