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0 °C

3-Bromothiophene (11 g, 67 mmol) dissolved in hexanes (110 ml) was cooled to −20 C in acetone/water bath, and n-Bu Li (28 ml, 71 mmol, 2.5 N solution in hexanes) was added slowly, over 10 min, then stirred 10 min at −20 C. THF was added (10 ml) over 5 min with rapid stirring. Precipitate formed after about ⅔ of addition. After adding all of the THF, the reaction mixture was stirred 20 min at −20 C, then 20 ml hexanes was added and the reaction mixture was allowed to warm to zero degrees C. N-Methoxy-N-methyl-butyramide (9.29 g, 71 mmol) dissolved in 20 ml hexanes was added via cannula over 5 minutes, and the reaction mixture was stirred at zero degrees C. for 1.5 hours. The reaction mixture was quenched with water, then 1 N HCl (75 ml), extracted twice with ether, washed 1 N HCl, brine, and dried over magnesium sulfate. Solvent was removed under reduced pressure to give an oil, which was chromatographed by flash chromatography (5% EtOAc/hexanes) to give 6.7 g, 64% of 1-Thiophen-3-yl-butan-1-one as an oil.

1. customPrecipitate formed after
2. additionabout ⅔ of addition
3. stirringthe reaction mixture was stirred 20 min at −20 C
4. additionwas added via cannula over 5 minutes
5. stirringthe reaction mixture was stirred at zero degrees C
6. waitfor 1.5 hours
7. customThe reaction mixture was quenched with water
8. extraction1 N HCl (75 ml), extracted twice with ether
9. washwashed 1 N HCl, brine
10. dry with materialdried over magnesium sulfate
11. customSolvent was removed under reduced pressure
12. customto give an oil, which
13. customwas chromatographed by flash chromatography (5% EtOAc/hexanes)