General procedure: 5-bromo-2-(tert-butoxycarbonyl)isoindoline (1.2 g, 4 mmol), bis(pinacolato)diboron (2 g, 8 mmol) and DMSO (20 mL) were added to the reaction flask followed by AcOK (1.6 g, 16 mmol). Pd(dppf)Cl2-CH2Cl2 (327 mg, 0.4 mmol) was added under nitrogen protection. The reaction mixture was heated and stirred at 90°C for 12 hours. After completion of the reaction, it was cooled to room temperature and the reaction solution was poured into EtOAc/H2O (300 mL/100 mL). The organic phase was separated, washed with brine (100 mL), dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (PE/EtOAc (v/v) = 20/1) to afford N-Boc-isoindoline-5-boronic acid pinacol ester as a yellow oil (1 g, 73%).MS (ESI, cationic) m/z: 290.2 [M-56 + 1]; 1H NMR (400 MHz, CDCl3) δ (ppm): 7.68- 7.74 (m, 2H), 7.23-7.30 (m, 1H), 4.64-4.70 (m, 4H), 1.53 (s, 9H), 1.36 (s, 12H).
