Reaction Steps
To a solution of diisopropyl (E)-3-acetoxymethyl-4-hydroxybut-1-enylphosphonate (3 g, 9.7 mmol ) and imidazole (1.7 g, 25 mmol) in anhydrous THF (60 ml) at 0° C. was added t-butyldiphenylsilylchloride (3.2 ml, 12.7 mmol). After stirring at room temperature for 3 h, the solvent was removed and the residue was partitioned between chloroform (100 ml) and brine (30 ml). The organic phase was dried (MgSo4), evaporated in vacuo and chromatographed on silica gel, eluting with chloroform of increasing polarity to chloroform-methanol (100:1) to give diisopropyl (E)-3-acetoxymethyl-4-t-butyldiphenylsilyloxybut-1-enylphosphonate as an oil (5 g, 94%); υmax (film) 3071, 3050, 2977, 2931, 2858, 1743, 1630, 1582, 1472,and 1425 cm-1 ; δH (CDCl3) 1.05 [9H, s, C(CH3)3 ], 1.26 (3H, d, J 6 Hz, CH3CH), 1.27 (3H, d, J 6 Hz, CH3CH), 1.32 [6H, d, J 6.3 Hz, (CH3)2CH], 1.98 (3H, s, CH3CO), 2.74 (1H, m, CH), 3.72 (2H, m, CH2), 4.22 (2H, m, CH2), 4.65 (2H, m, 2×CH(CH3)2 ], 5.76 (1H, ddd, J 1, 17 and 18 Hz, PCH=CH), 6.99 (1H, ddd, J 7, 17 and 22 Hz, PCH=CH), 7.3-7.7 (10H, m, 2×C6H5) (Found: C, 63.42; H, 8.22%. C29H43O6PSi requires C, 63.71; H, 7.93%.).
