tert-Butyl-3-bromopropionate

tert-Butyl-3-bromopropionate

To a solution of 3-bromopropionic acid (6.0 kg, 39.2 mol) in dichloromethane (60 L) at 0° C. was added tert-butanol (0.6 L) and conc. sulfuric acid (0.33 L). The resultant solution was cooled to −15° C. and isobutylene was bubbled through (11 kg, 196 mol). The reaction was then stirred for 3 hours at −5° C. before warming to 20° C. over 4 hours and was then stirred at this temperature for 15 hours. The reaction was quenched by cautious addition into saturated aqueous sodium bicarbonate solution (0.6 M, 72 L, 43.2 mol). The layers were then separated and the organic layer was washed with saturated aqueous sodium bicarbonate solution (2×48 L) followed by deionised water (48 L). This washing cycle was repeated and the pH of the aqueous layer was measured and was shown to be above pH 7. Potassium carbonate (90 g, 1.5% w/w) was added to the organic layer before concentrating the solution to a volume of 9 L by distillation at atmospheric pressure. Tetrahydrofuran (40 L) was added and the remainder of the dichloromethane was removed by distillation at atmospheric pressure to give a solution (12 L) of the title compound (5.27 kg, 25.2 mol, 64% yield) in tetrahydrofuran that was used directly in the next step;

¹H-NMR (CDCl₃, 300 MHz,) δ: 1.45 (s, 9H), 2.80 (t, 2H), 3.53 (t, 2H); LRMS (El): m/z [MH⁺] 209 (⁷⁹Br).