反应详情

49.1 g (499 mmol) of trimethylsilyl acetylene was dissolved in 250 mL of anhydrous tetrahydrofuran, and the inner temperature was lowered to about −55° C., and then 210 mL (525 mmol) of 2.5 M n-BuLi in n-hexane was added thereto over about 25 minutes with maintaining the inner temperature below −30° C. After stirring for about 40 minutes, 52.9 g (499 mmol) of ethyl fluoroacetate was added to the reaction mixture over 5 minutes with maintaining the inner temperature below −25° C., and then 74.4 g (524 mmol) of BF3.OEt was added thereto over 15 minutes with maintaining the inner temperature −55° C. to −65° C. After finishing the addition, the reaction mixture was stirred at 20° C. for 2 hours, and 250 mL of 10% ammonium chloride aqueous solution was added thereto to finish the reaction. The organic layer was separated, and the aqueous layer was extracted with 200 mL of ethylacetate. The combined organic phase was washed with 250 mL of brine, and concentrated under reduced pressure. The residue was distilled under vacuum at 10 mbar and 68° C. to give the compound of formula (9) (67.3 g, 85%) as clear oil.

1. customwas lowered to about −55° C.
2. temperatureover about 25 minutes with maintaining the inner temperature below −30° C
3. temperaturewith maintaining the inner temperature below −25° C.
4. additionOEt was added
5. temperatureover 15 minutes with maintaining the inner temperature −55° C. to −65° C
6. additionthe addition
7. stirringthe reaction mixture was stirred at 20° C. for 2 hours
8. customthe reaction
9. customThe organic layer was separated
10. extractionthe aqueous layer was extracted with 200 mL of ethylacetate
11. washThe combined organic phase was washed with 250 mL of brine
12. concentrationconcentrated under reduced pressure
13. distillationThe residue was distilled under vacuum at 10 mbar and 68° C.