反应详情

温度

-78 °C

2M LDA in THF (1.83 mL, 3.66 mmol) was added dropwise under N2, to a stirred solution of diethyl (4-nitrobenzyl)phosphonate (1.00 g, 3.66 mmol) in THF (10 mL) at −78° C. After 1 hour, iodomethane (0.456 mL, 7.32 mmol) was added dropwise and the mixture stirred at −78° C. for 30 min then allowed to warm to room temperature during 3-4 h. Water (10 mL) was then added slowly followed by EtOAc (20 mL). The layers were separated and the aqueous phase was extracted with EtOAc (3×20 mL). The organic phases were combined, dried (MgSO4), concentrated in vacuo, and the residue purified by chromatography over silica gel eluting with 10% EtOAc in hexanes to afford 180 mg of pure diethyl [1-(4-nitrophenyl)ethyl]phosphonate (yield: 17%) and 680 mg of a mixture of diethyl (4-nitrobenzyl)phosphonate and diethyl [2-(4-nitrophenyl)propan-2-yl]phosphonate.

1. temperatureto warm to room temperature during 3-4 h
2. customThe layers were separated
3. extractionthe aqueous phase was extracted with EtOAc (3×20 mL)
4. dry with materialdried (MgSO4)
5. concentrationconcentrated in vacuo
6. customthe residue purified by chromatography over silica gel eluting with 10% EtOAc in hexanes