Ethyl 4-bromocrotonate

623-70-1

37746-78-4

General procedure for the synthesis of ethyl (E)-4-bromobut-2-enoate from ethyl crotonate: To a round-bottomed flask containing ethyl (2E)-but-2-enoate (10.9 g, 87.6 mmol) and carbon tetrachloride (100 mL), N-bromosuccinimide (NBS, 17 g, 96 mmol) and azobisisobutyronitrile (AIBN, 4.3 g, 26 mmol). The reaction mixture was stirred at 80 °C for 12 hours. After completion of the reaction, the reaction mixture was diluted with dichloromethane (DCM) and washed sequentially with saturated sodium bicarbonate solution, water and brine. The organic layer was dried with anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent to give ethyl (E)-4-bromobut-2-enoate (7.5 g, 44% yield) as an oil.