Triethyl phosphite → Diethyl 3-Bromobenzylphosphonate
Reaktionsgleichung
[Br:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([CH2:8]Br)[CH:3]=1.[P:10]([O:17]CC)([O:14][CH2:15][CH3:16])[O:11][CH2:12][CH3:13].P([O-])([O-])[O-]>>[CH2:12]([O:11][P:10]([CH2:8][C:4]1[CH:5]=[CH:6][CH:7]=[C:2]([Br:1])[CH:3]=1)(=[O:17])[O:14][CH2:15][CH3:16])[CH3:13]Komponenten
4
Reaktionsbedingungen
- Temperatur
- 130 °C
Versuchsvorschrift
To 1-bromo-3-(bromomethyl)benzene (100 g, 400 mmol) in a 500 mL round-bottom flask under nitrogen was added triethyl phosphite (69.6 mL, 400 mmol) and the solution was heated to 130° C. The apparatus was set up ready for distillation. As the heating block reached 130° C. the mixture began to reflux and a large volume of colourless liquid was allowed to distil off. Analysis of the reaction by hplc after 40 min showed some starting material so another 0.5 eq of the phosphite was added and heating with distillation continued. The reaction was then heated under vacuum: the excess phosphite was distilled off under vacuum (130° C. heater and 15 mbar, gradually going down to 0.5 mbar). This gave a colorless oil 120.8 g. HPLC 2.20 min (ret time), 97%; LC-MS m/z 307, 309 (M+H)+, 1.01 min (ret time).