A mixture of 4-{2-[({[(4-Methylphenyl)sulfonyl]amino}carbonyl)oxy]ethyl}phenylboronic acid (100 mg, 0.28 mmol), 4-phenylimidazole (40 mg, 0.28 mmol), Copper(II) acetate (50 mg, 0.28 mmol), triethylamine (115 μL, 0.83 mmol), molecular sieves 4A (100 mg), and dichloromethane (4 mL) was stirred at room temperature for 1 week. Insoluble materials were removed by Celite pad, the filtrate was diluted with dichloromethane, and washed with water. The combined organic phase was dried (MgSO4) and concentrated under reduced pressure. The residue was purified by TLC with dichloromethane/methanol (10:1) to afford 58 mg (46%) of the title compound as white solids: MS (ESI) m/z 462 [M+H]+, 460 [M−H]−, 1H-NMR (DMSO-d6) δ 2.35 (3H, s), 2.88 (2H, t, J=6.5 Hz), 4.23 (2H, t, J=6.5 Hz), 7.22-7.43 (7H, m), 7.62 (2H, d, J=8.3 Hz), 7.74 (2H, d, J=8.3 Hz), 7.86 (2H, d, J=7.3 Hz), 8.26 (1H, s), 8.32 (1H, s).
