Dimethyl malonate → Dimethyl 2-(2-bromoallyl)malonate

Participants

Reaction Steps

To a flask under nitrogen was added MeOH (67 mL), and sodium metal (1.15 g, 0.05 g atom) was added in portions over 30 min. To the resulting solution dimethyl malonate (13.2 g, 0.1 mol) in MeOH (10 mL) was added from a dropping funnel over 30 min. The solution was cooled to 0°, and 2,3-dibromopropene (12 g, 0.05 mol) in MeOH (15 mL) was added over 40 min. After a further 45 min at 0°, the pH of the mixture was neutral to litmus paper. The reaction medium was then concentrated under reduced pressure and the residue was dissolved in EtOAc (100 mL) and the resulting solution washed with distilled H2O (100 mL). The aqueous phase was re-extracted with Et2O (100 mL) and the combined organic phases were washed with brine, dried (MgSO4), concentrated under reduced pressure and purified by distillation (82°-84°/1 Torr) to give the title compound as a colorless liquid (8.3 g, 66% yield): 1H NMR (400 MHz, CDCl3) δ5.69 (m, 1H, olefinic), 5.48 (d, J=1.9 Hz, 1H, olefinic), 3.81 (t, J=7.63 Hz, 1H), 3.75 (s, 6H), 3.02 (dd, J=0.95, 7.63 Hz, 2H); 13CNMR (100 MHz, CDCl3) δ8 168.30, 129.18, 119.68, 52.59, 50.28, 40.36.

Provenance & Evidence