反応 #1833252

反応方程式

1,2,2-trifluorotrichloroethane

n-Butyllithium

2,2-Difluorobenzo[d][1,3]dioxole

1,2,2-Trifluorotrichloroethane

→

title compound

収率 74.9%

4-Chloro-2,2-difluorobenzo[d][1,3]dioxole

収率 74.9%

溶媒

tetrahydrofuran

tetrahydrofuran

反応条件

後処理

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   その他the temperature below −70° C
3. 3
   温度cooled to −65° C
4. 4
   workup.ADDITIONto remain between −60° C. and −65° C. during the addition
5. 5
   温度to warm to room temperature
6. 6
   その他partitioned between diethyl ether and water
7. 7
   濃縮The organic phase was concentrated

実験手順

2,2-Difluorobenzo[d][1,3]dioxole (6.3 g, 39.8 mmol) was dissolved in tetrahydrofuran (66 mL) and cooled to −78° C. n-Butyllithium (2.5 M solution in hexanes; 16.74 mL, 41.8 mmol) was added dropwise, keeping the temperature below −70° C. The reaction mixture was then stirred at −78° C. for 1 h to ensure complete deprotonation. 1,2,2-Trifluorotrichloroethane (14.93 g, 80 mmol) was dissolved in tetrahydrofuran (33 mL) and cooled to −65° C. The lithiate was transferred via cannula into the solution of 1,2,2-trifluorotrichloroethane at a rate that allowed the temperature to remain between −60° C. and −65° C. during the addition. The reaction mixture was then allowed to warm to room temperature and partitioned between diethyl ether and water. The organic phase was concentrated and the product was flashed through 100 g of silica gel using hexane as a solvent to provide the title compound as a clear oil (5.74 g, 74.8%): 1H NMR (400 MHz, CDCl3) δ 7.08 (dd, J=8.2, 1.4 Hz, 1H), 7.03 (t, J=8.0 Hz, 1H), 6.97 (dd, J=7.9, 1.5 Hz, 1H); EIMS m/z 192.

出典