Reaction Steps
A mixture of dimethyl 2,5-dimethoxybenzylphosphonate (2.92 g, 11.2 mmol) and sodium hydride (60% in oil, 1.08 g, 27.0 mmol) in dry DMF (92 ml) was cooled with in an ice-bath under argon. To this was added dropwise a solution of 4-(6-hydroxyhexyloxy)benzaldehyde (13) (2.50 g, 11.3 mmol) in dry DMF (55 ml). The reaction mixture was stirred at 6° C. for 1.5 h and then at room temperature for 4 h. Ether (300 ml) and water (250 ml) were added and the mixture shaken well. The organic layer was separated and washed with water (4×250 ml), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography over silica (dichloromethane/methanol; 19:1 yield (14) (1.89 g, 47%) as an oil; δH (CDCl3) 1.46 (4 H, m, CH2), 1.60 (2 H, m, CH2), 1.79 (2 H, m, CH2), 3.65 (2 H, t, J =6.6 Hz, OCH2), 3.81 (3 H, s, OCH3), 3.83 (3 H, s OCH3), 3.96 (2 H, t, J=6.5 Hz, OCH2), 6.76 (1 H, dd, JH3', JH4 '=8.9 Hz, JH6',H4' =3.0 Hz, H4'), 6.82 (1 H, d, JH4',H3' =8.9 Hz, H3'), 6.87 and 7.45 (4 H, AA'BB', PhH), 7.03 (1 H, d, J=16.5 Hz, vinylic H), 7.13 (1 H, d, JH4',H6' =3.0 HZ, H6') and 7.31 H, d, J=16.5 Hz, vinylic H); δc (CDCl3) 25.5, 25.6, 29.2, 32.6, 55.7, 56.2, 62.8, 67.8, 111.3, 112.2, 113.1, 114.5, 120.7, 127.6, 127.7, 128.7, 130.4, 151.2, 153.7 and 158.7.
