Reaction Steps
To a solution of (E)-1,5-bis(4-tert-butyldimethylsilyloxy-3-methoxyphenyl)-pent-4-ene-1,3-dione (459 mg, 0.80 mmol) in anhydrous diethyl ether (8 ml) was added sodium (20 mg, 0.88 mmol). The mixture was stirred for 18 h, when all the sodium had been consumed, forming a yellow solid. The diethyl ether was removed under vacuum, and the yellow oily solid was dissolved in acetone (8 ml). Methyl iodide (45 μl, 0.72 mmol) was added to this mixture and stirred overnight at room temperature. The acetone was removed under vacuum, and the residue was taken up in ethyl acetate, washed with water, dried (MgSO4 (anh)), filtered and concentrated in vacuo. The residue was purified on silica gel column using dichloromethane/petroleum ether (1:1 to 1:0) to give 1,5-bis(4-tert-butyldimethylsilyloxy-3-methoxyphenyl)-2-methylpent-4-ene-1,3-dione (281 mg, 60%) as a yellow oil: 1H NMR (400 MHz, CDCl3) δ 0.16 (6H, s, 2×CH3), 0.18 (6H, s, 2×CH3), 0.99 (18H, br s, 2×(CH3)3)), 1.54 (3H, d, J=7.0 Hz, CH3), 3.83 (3H, s, OCH3), 3.85 (3H, s, OCH3), 4.66 (1H, q, J=7.0 Hz, H-2), 6.69 (1H, d, J=16 Hz, H-4), 6.83 (1H, d, J=8.4 Hz, H-5′), 6.87 (1H, d, J=8.4 Hz, H-5′), 7.00 (1H, d, J=2.0 Hz, H-2′), 7.03 (1H, dd, J=8.4, 2.0 Hz, H-6′), 7.53-7.58 (2H, m, ArH), 7.60 (1H, d, J=16.0 Hz, H-5) ppm.
