반응 #2260204

반응 방정식

thiophene

n-butyllithium

n-butyllithium

2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

N-fluorobenzenesulfonimide

→

title compound

수율 21.0%

2-(5-Fluorothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

수율 21.0%

용매

THF

THF

THF

반응 조건

후처리

1. 1
   기타the temperature below −70° C
2. 2
   기타to rise to −10° C.
3. 3
   온도was subsequently cooled to −78° C
4. 4
   workup.WAITto continue at −78° C. for 30 min
5. 5
   기타quenched with saturated aqueous ammonium chloride (10 mL)
6. 6
   기타The organic layer was separated
7. 7
   추출the aqueous phase was extracted with EtOAc (3×15 mL)
8. 8
   건조dried over sodium sulfate
9. 9
   기타After removal of solvent
10. 10
    기타the residue was purified by flash chromatography (petroleum ether/ethyl acetate=20:1)

실험 절차

To a solution of thiophene (252 mg, 2.99 mmol) in THF (3.5 mL) at −78° C. was added n-butyllithium (2.5M, 1.3 mL, 3.2 mmol) dropwise to keep the temperature below −70° C. The solution was stirred for 40 minutes at −78° C. A solution of N-fluorobenzenesulfonimide (987 mg, 3.1 mmol) in THF (5 mL) was added over a period of 20 minutes. The temperature of the mixture was allowed to rise to −10° C. and was subsequently cooled to −78° C. To the mixture was added n-butyllithium (2.5M, 1.3 mL, 3.2 mmol) and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (580 mg, 3.1 mmol) in THF (2 mL). The reaction was allowed to continue at −78° C. for 30 min and then quenched with saturated aqueous ammonium chloride (10 mL). The organic layer was separated and the aqueous phase was extracted with EtOAc (3×15 mL). The organic layers were combined and dried over sodium sulfate. After removal of solvent, the residue was purified by flash chromatography (petroleum ether/ethyl acetate=20:1) to give the title compound (143 mg, 21%). 1H NMR (400 MHz, CDCl3) δ ppm 1.32 (s, 12H), 6.55 (d, J=3.6 Hz, 1H), 7.27 (d, J=3.6 Hz, 1H).

출처