“…Purification by silica gel column chromatography (PE/EtOAc 6:1) to afford 3a (55 mg, 94%) as a white solid; mp 120.2-121.4 °C. 1 H NMR (500 MHz, CDCl 3 ): = 7.58 (d, J = 7.4 Hz, 2 H), 7.37 (m, 3 H), 7.09 (t, J = 7.9 Hz, 2 H), 6.77 (t, J = 7.3 Hz, 1 H), 6 57, 142.11, 137.54, 129.44, 129.15, 129.00, 125.66, 124.70, 119.51, 116.81, 61.29, 52.39, 39.19, 29.54 19, 154.07, 138.01, 137.16, 129.30, 129.02, 126.01, 120.01, 118.25, 114.59, 62.20, 55.63, 52.24, 39.13, 29.49…”