“…The product (55 mg, 63%) as a colorless oil was purified with silica gel chromatography (petroleum ether:ethyl acetate = 20:1). 1 H NMR (400 MHz, chloroform-d) δ 7.55 (d, J = 8.3 Hz, 2H), 7.44 (d, J = 8.2 Hz, 2H), 6.56 (d, J = 15.9 Hz, 1H), 6.30 (dt, J = 15.8, 7.2 Hz, 1H), 5.02 (ddd, J = 48.7, 6.8, 4.6 Hz, 1H), 4.27 (q, J = 7.1 Hz, 2H), 2.96−2.73 (m, 2H), 1.30 (t, J = 7.1 Hz, 3H).19 F NMR (376 MHz, chloroform-d) δ −62.6, −191.2 (dt, J = 49.1, 24.7 Hz) 13.…”