A mixture of the above urea (0.022 g, 0.050 mmol), phenylboronic acid (0.012 g, 0.1 mmol), copper (II) acetate (0.014 g, 0.075 mmol), pyridine (0.01 mL, 0.1 mmol) and molecular sieves (4 Å activated, 0.030 g) in methylene chloride (2 mL) was stirred at room temperature for 14 h under air. After filtration through diatomaceous earth, the filtrate was concentrated in vacuo and purified by flash chromatography (EtOAc 100% to EtOH 100%) to give the title compound as a yellow-white solid (0.02 g, 73%), mp 142-143° C.; 1H NMR (DMSO) δ 1.26(s, 9H), 2.53(t, 4H) 2.83(t, 2H), 3.57(t, 4H), 4.24(t, 2H), 6.34(s, 1H), 6.94(d, 1H), 7.40(d, 1H), 7.55(m, 7H), 7.90(d, 1H), 8.15(d, 1H), 8.82(s, 1H), 8.92(s, 1H); MS (CI) 514(M++H).
