Реакция #1833219

Уравнение реакции

1,1,2-Trichloro-1,2,2-trifluoroethane

2,2,6,6-Tetramethylpiperidine

n-butyllithium

NH4Cl

5-Bromo-2,2-difluorobenzo[d][1,3]dioxole

→

title compound

Выход 28.1%

5-Bromo-4-chloro-2,2-difluorobenzo[d][1,3]dioxole

Выход 28.1%

Растворители

water

diethyl ether

tetrahydrofuran

Условия реакции

Обработка

1. 1
   workup.STIRRINGthe mixture was stirred for 2 h at −75° C
2. 2
   workup.STIRRINGstirring
3. 3
   workup.WAITwas continued for 1.5 h
4. 4
   ПромывкаThe ether phase was washed with saturated NaCl (10 mL)
5. 5
   Сушкаdried (Na2SO4)
6. 6
   Другоеevaporated under vacuum
7. 7
   ДругоеThe residue was purified by chromatography on silica with hexane
8. 8
   Другоеrepurified by reverse-phase

Методика

2,2,6,6-Tetramethylpiperidine (2.1 mL, 1.8 g, 12 mmol) was dissolved in dry tetrahydrofuran (15 mL), cooled to −75° C. and treated with n-butyllithium (n-BuLi, 2.5 M; 4.8 mL, 12 mmol), and the mixture was stirred for 30 min at −75° C. 5-Bromo-2,2-difluorobenzo[d][1,3]dioxole (2.0 g, 8.4 mmol) was added, and the mixture was stirred for 2 h at −75° C. 1,1,2-Trichloro-1,2,2-trifluoroethane (2.4 mL, 3.8 g, 20 mmol) was added and stirring was continued for 1.5 h. Saturated NH4Cl (10 mL) was added, and the mixture was shaken with diethyl ether (30 mL) and water (20 mL). The ether phase was washed with saturated NaCl (10 mL), dried (Na2SO4) and evaporated under vacuum. The residue was purified by chromatography on silica with hexane and then repurified by reverse-phase HPLC using 75% acetonitrile to give the title compound as a clear liquid (640 mg, 28%): 1H NMR (400 MHz, CDCl3) δ 7.38 (dd, J=8.5, 5.1 Hz, 1H), 6.90 (dd, J=9.0, 4.7 Hz, 1H); EIMS m/z 332.

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