1H NMR (400 MHz, CDCl3) δ 7.98 (d, J = 7.7 Hz, 1H), 7.37 (d, J = 7.4 Hz, 1H), 7.33 (d, J = 7.5 Hz, 2H), 7.23 (s, 3H), 7.15 (d, J = 7.0 Hz, 2H), 6.08 (s, 1H), 2.96 (dd, J = 9.4, 5.6 Hz, 1H), 2.82 (dd, J = 21.4, 18.7 Hz, 2H), 2.45 (s, 2H), 2.06 – 1.81 (m, 5H). 13C NMR (101 MHz, CDCl3) δ 202.43, 143.23, 141.52, 134.74, 133.16, 131.81, 128.73, 128.33, 128.11, 126.87, 126.71, 124.98, 122.39, 43.07, 32.50, 30.34, 28.00, 25.24, 24.45. HRMS (ESI): calcd for C21H21O [M + H]: 289.1592, found: 289.1595.