反应详情

温度

-78 °C

Butyllithium (10.8 ml, 21.60 mmol, 2.0M) was added dropwise at 0° C. to a stirred solution of 4-(2-hydroxyethyl)-2,2-dimethyl-1,3-dioxolane (2.87 g, 19.60 mmol) and a crystal of 4-phenylazodiphenylamine indicator in THF (7 ml) under N2. The resulting solution was added dropwise at -78° C. to a stirred solution of N-methyl-N-(2-bromoethyl) phosphoramidic dichloride (5.00 g, 19.60 mmol) in THF (10 ml) under N2. The mixture was allowed to stir under N2 at -78° C. for 3 hr, at which time the purple mixture turned yellow. The mixture was warmed to room temperature and the solvent removed under reduced pressure. The residue was purified by chromatography (1:4 EtOAc: hexanes) and the product 16a isolated as an oil (4.77 g, 67%): Rf 0.61 (1:1 EtOAc:hexanes); 1H NMR (CDCl3) 4.26(dt, 2H, J= 8.44 Hz), 4.17(t, 1H, J=6.53 Hz), 4.06(t, 1H, J=7.06 Hz), 3.54(t, 1H, J=7.10 Hz), 3.44(m, 4H), 2.76(d, 3H, J=12.76 Hz), 1.95(dt, 2H, J=6.24 Hz), 1.67(d, 6H, 15.63 Hz); 31P NMR (CDCl3) -8.07 ppm.

1. temperatureThe mixture was warmed to room temperature
2. customthe solvent removed under reduced pressure
3. customThe residue was purified by chromatography (1:4 EtOAc: hexanes)