To a stirred solution of 5-bromo-3-chloro-1H-indole-2-carboxylic acid ethyl ester (500 mg, 1.86 mmol) and 3,5-dichlorophenyl boronic acid (530 mg, 2.78 mmol) in a mixture of MeCN (26 mL) and i-PrOH (3.3 mL) at room temperature under argon, was added Pd(OAc)2 (12 mg, 0.05 mmol), Ph3P (40 mg, 0.15 mmol) and Na2CO3 (2M aq., 16 mL) and the resulting mixture was heated at reflux for 3 h. After cooling to room temperature the reaction was diluted with water (20 mL) and extracted with EtOAc (3×30 mL). The combined organic extracts were washed with water, brine and dried (MgSO4). Solvent removal and purification by chromatography afforded the sub-title compound (430 mg, 69%).
