Diethyl 1H-indole-2,6-dicarboxylate (Intermediate A, 3.5 g, 13.6 mmol), 2,2-difluoropropane-1,3-diyl bis(4-methylbenzenesulfonate) (6.0 g, 14.3 mmol) and K2CO3 (3.9 g, 28.5 mmol) are mixed in DMF (36 mL) and the reaction mixture is separated into 3 fractions. Each fraction is heated in a microwave reactor at 135° C. for 1 h. The 3 fractions are combined, and water (300 mL) and EtOAc (300 mL) are added. The aqueous layer is separated and extracted with EtOAc (3×100 mL). The organic layers are combined, washed with water (3×200 mL), dried (Na2SO4) and concentrated. The crude compound is purified by flash column chromatography using EtOAc in heptane to afford the title compound (4.7 g, 59% pure, 38% yield).
