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

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.

1. additionwas added in portions over 30 min
2. temperatureThe solution was cooled to 0°
3. concentrationThe reaction medium was then concentrated under reduced pressure
4. dissolutionthe residue was dissolved in EtOAc (100 mL)
5. washthe resulting solution washed with distilled H2O (100 mL)
6. extractionThe aqueous phase was re-extracted with Et2O (100 mL)
7. washthe combined organic phases were washed with brine
8. dry with materialdried (MgSO4)
9. concentrationconcentrated under reduced pressure
10. distillationpurified by distillation (82°-84°/1 Torr)

ORD record

ord-da6cba62b4db4d98be2e044db16b4faa

Source dataset

uspto-grants-1998_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05808085