A mixture of 3-bromo-1H-indolecarboxylic acid ethyl ester (0.50 g, 1.87 mmol), phenylboronic acid (0.27 g, 2.25 mmol), 2 M aqueous sodium carbonate (8 mL), tetrakis(triphenylphosphine)palladium (0) (0.20 g, 0.17 mmol) in ethanol (16 mL) and toluene (30 ml) was heated at 65° C. for 16 h and then cooled. The reaction mixture was diluted with 1 N hydrochloric acid and then extracted with ethyl acetate. The organic extracts were washed with water, dried over magnesium sulfate and concentrated. Flash silica gel chromatography using ethyl acetate/hexane as elutant gave 0.34 g (68%) of 3-phenyl-1H-indolecarboxylic acid ethyl ester as a pink solid: 1H NMR (DMSO-d4) δ 1.18 (t, J=7.2 Hz, 3H), 4.22 (q, J=7.2 Hz, 2H), 7.07-7.11 (m, 1H), 7.29-7.33 (m, 1H) 7.45 (dd, J=8.3, 0.8 Hz, 1H), 7.48-7.50 (m, 5H), 7.50 (dd, J=8.3, 0.8 Hz, 1H), 11.90 (br s, 1H); MS (ESI) m/z 266 (MH+); 264 ([M−H]−).
