To a solution of allylcyanide (1; 4g, 59.62 mmol) in tert-butanol (6ml) and petroleum ether (27ml) was added bromine (9.5 g, 59.62 mmol) at 15, and then stirred at room temperature for 20 minutes. A solution of 21% sodium ethoxide (19.3 g, 59.62 mmol) was added dropwise to the mixture and the solid was filtered off. The filtrate was distilled under reduced pressure to give 4-bromo-2-butenenitrile (3) 8) as a liquid (4.6 g, 52.8%).
