“…With the addition of Br 2 finished, the reaction mixture was stirred for 4 h and allowed slowly to reach room temperature. The reaction mixture was then washed with aqueous Na 2 To induce oxidation of residual benzaldehyde and to make the purification easier, the crude product was exposed to air and daylight for about 24 h. Two chromatographic columns were necessary to obtain a pure product. A column of silica gel (petroleum ether/EtOAc 97:3) followed by a separation on silica gel impregnated with AgNO 3 (petroleum ether/EtOAc 98:2) afforded 5 as a colourless oil (0.09 g, 61 %, Z/E 91:9 1 H NMR (300 MHz, CDCl 3 ): δ = 2.43 (q, J = 7.6 Hz, 2 H), 2.86 (t, J = 7.6 Hz, 2 H), 6.13 (t, J = 7.6 Hz, 1 H), 7.00-7.36 (m, 13 H), 7.49 (dd, J = 7.9, 1.1 Hz, 1 H) ppm.…”