反应详情

A mixture of 2-[di-(t-butoxycarbonyl)]amino-9-hydroxy-6-methoxypurine (0.62 g, 1.6 mmol), triphenylphosphine (0.43 g, 1.6 mmol), and diisopropyl (E)-3-(t-butyldiphenylsilyloxy)methyl-4-hydroxybut-1-enylphosphonate (0.6 g, 1.2 mmol) in anhydrous THF (15 ml) at 0° C. was treated dropwise, slowly, with diethyl azodicarboxylate (0.25 g, 1.6 mmol). After stirring overnight at room temperature, the solvent was removed in vacuo and the residue chromatographed on silica gel, eluting with acetone-hexane (1:2) to give (E)-9-[2-(t-butyldiphenylsilyloxy)methyl-4(diisopropoxyphosphoryl)but-3-enyloxy]-2-[di-(t-butoxycarbonyl)]amino-6-methoxypurine as a gum (0.7 g, 66%); υmax (KBr) 2977, 2932, 2858, 1792, 1757, 1734, 1592, 1472, and 1427 cm-1 ; δH (CDCl3) 1.06 [9H, s, C(CH3)3 ], 1.30 [12H, s, 2×CH(CH3)2 ], 1.43 (18H, s, 2×C(CH3) 3 ], 2.92 (1H, CH), 3.85 (2H, m, CH2), 4.15 (3H, s, OCH3), 4.4-4.75 [4H, CH2, 2×CH (CH3)2 ], 5.91 (1H, ddd, J 1, 17 and 19 Hz, PCH=CH), 6.77 (1H, ddd, J 8, 17 and 25Hz, PCH=H) , 7.3-7.85 (11H, m, 2×C6H5, H-8) (Found: C, 59.77; H, 7.52;N, 7.79%. C43H62N5O10PSi requires C, 59.50; H, 7.20; N, 8.07%).

1. additionwas treated dropwise
2. customthe solvent was removed in vacuo
3. customthe residue chromatographed on silica gel
4. washeluting with acetone-hexane (1:2)