1H NMR (400 MHz, CDCl3) δ 7.57 (d, J = 7.8 Hz, 1H), 7.38 (d, J = 7.9 Hz, 3H), 7.34 (d, J = 5.4 Hz, 1H), 7.30 (d, J = 7.5 Hz, 2H), 7.27 (s, 1H), 7.22 (d, J = 7.5 Hz, 1H), 6.14 (s, 1H), 3.39 (s, 1H), 2.56 (d, J = 11.8 Hz, 2H), 2.49 (s, 2H), 2.45 (s, 3H), 2.15 (d, J = 14.4 Hz, 1H), 1.83 (dt, J = 18.3, 11.4 Hz, 1H). 13C NMR (101 MHz, CDCl3) δ 207.83, 141.77, 138.45, 137.62, 136.36, 131.76, 130.81, 128.32, 127.61, 126.91, 125.65, 125.07, 123.03, 44.40, 28.18, 27.13, 25.61, 20.84. HRMS (ESI): calcd for C20H21O [M + H]: 277.1592, found: 277.1598.