¹H NMR (400 MHz, CDCl₃) δ 8.00 (d, J = 7.6 Hz, 2H), 7.58 (t, J = 7.1 Hz, 1H), 7.49 (t, J = 7.3 Hz, 2H), 7.30 (d, J = 7.3 Hz, 2H), 7.14 (d, J = 7.6 Hz, 2H), 6.14 (d, J = 1.9 Hz, 1H), 3.67 – 3.52 (m, 1H), 2.58 (s, 2H), 2.48 (dd, J = 32.4, 14.1 Hz, 2H), 2.34 (s, 3H), 2.17 (d, J = 11.2 Hz, 1H), 1.93 – 1.83 (m, 1H). ¹³C NMR (101 MHz, CDCl3) δ 203.40, 138.89, 136.57, 136.34, 136.09, 132.98, 129.01, 128.71, 128.35, 124.93, 122.26, 41.37, 28.76, 27.24, 26.29, 21.07. HRMS (ESI): calcd for C₂₀H₂₁O [M + H]: 277.1592, found: 277.1594.