反应详情

A solution of diisopropyl (E)-4-hydroxy-3-hydroxymethylbut-1-enylphosphonate (5 g, 19 mmol), trimethyl orthoacetate (7 ml, 56 mmol) and p-toluenesulphonic acid (0.36 g, 1.9 mmol) in anhydrous THF (50 ml) was stirred at room temperature for 1.5 h. The solution was treated with water (5 ml), stirred for a further 30 min, then treated with triethylamine (0.1 ml). The solvent was removed in vacuo and the residue chromatographed on silica, eluting with chloroform-methanol (30:1) to give diisopropyl (E)-3-acetoxymethyl-4-hydroxybut-1-enylphosphonate as an oil (4.94 g, 85%);υmax (film) 3382, 2980, 2934, 2877, 2361, 2333, 1741, 1631, 1468,and 1455 cm-1 ; δH (CDCl3) 1.30 (6H, d, J 6.3 Hz, 2×CH3CH), 1.34 (6H, d, J 6 Hz, 2×CH3CH) 2.06 (3H, s, CH3CO), 2.40 (1H, br.s, D2O exchangeable OH), 3.68 (2H, m, CH2OH), 424 (2H, m, CH2), 4.64 [2H, m, 2×CH(CH3)2 ], 5.83 (1H, ddd, J 1, 17 and 19 Hz, PCH=CH), 6.67 (1H, ddd, J 8, 17 and 22 Hz, PCH=CH) (Found: C, 50.15; H, 8.46%; MH+ 309.1466. C13H17O6P.0.25 H2O requires: C, 49.95; H, 8.22%; MH+ 309.1467).

1. customThe solvent was removed in vacuo
2. customthe residue chromatographed on silica
3. washeluting with chloroform-methanol (30:1)