反应详情

温度

-78 °C

1,1-Dibromo-4-methyl-pent-1-ene 6 (40 g, 165.9 mmol) was dissolved in dry THF (120 mL) and cooled to −78° C. While stirring, n-butyllithium (1.6 M solution in hexane, 190.8 mL, 305 mmol) was added dropwise in a few minutes. After 1 hour, ethyl chloroformate (15 mL, 154.5 mmol) was added, and the reaction was stirred overnight during which it warmed to room temperature. It was poured onto water and extracted with ether (3×250 mL), dried on magnesium sulfate and evaporated. The light oil was flash chromatographed on a silica gel column, and the compound was eluted with 10% ether in pet ether to afford 5-methyl-hex-2-ynoic acid ethyl ester 7 (23.6 g, 92%).

1. stirringthe reaction was stirred overnight during which it
2. temperaturewarmed to room temperature
3. additionIt was poured onto water
4. extractionextracted with ether (3×250 mL)
5. customdried on magnesium sulfate
6. customevaporated
7. customchromatographed on a silica gel column
8. washthe compound was eluted with 10% ether in pet ether