Triethyl phosphite → Diethyl 3-Bromobenzylphosphonate

Participants

Reaction Conditions

Reaction Steps

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 distill off. Lab HPLC of the reaction 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 and the excess phosphite was distilled off under vacuum (130° C. heater and 15 mbar, gradually going down to 0.5 mbar). This gave 120.8 g (98%) of a colourless oil that the lab HPLC showed to be 97% pure with a 2.20 min retention time. LC-MS m/z 307, 309 (M+H)+, 1.01 min (ret time).

Provenance & Evidence