Under nitrogen protection, 6-bromo-1H-indole (25 g, 0.128 mol), pinacol ester of bisboronic acid (48.58 g, 0.191 mol), Pd(dppf)Cl2 (5.2 g, 5 mol%) and KOAc (37.55 g, 0.383 mol) were dissolved in DMF (500 ml). The reaction mixture was stirred at 120°C for several hours. After completion of the reaction, extraction was carried out with ethyl acetate and the organic phase was dried with magnesium sulfate. Purification by column chromatography (eluent: hexane/ethyl acetate=10:1, v/v) afforded 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (20.15 g, 65% yield).
