Reaction #1833253

Reaction equation

diethyl ether

N-Butyllithium

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

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

→

title compound

Yield 77.0%

2-(7-Chloro-2,2-difluorobenzo[d][1,3]dioxol-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Yield 77.0%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Otherthe temperature below −65° C
2. 2
   Otherthe temperature below −65° C
3. 3
   Temperatureto warm to room temperature
4. 4
   Extractionextracted with water (2×100 mL)
5. 5
   ExtractionThe product was extracted with diethyl ether
6. 6
   Otherthe organic phase was dried
7. 7
   Concentrationconcentrated under vacuum

Procedure

4-Chloro-2,2-difluorobenzo[d][1,3]dioxole (3 g, 15.58 mmol) was dissolved in tetrahydrofuran (50 mL) and cooled to −75° C. N-Butyllithium (2.5 M in hexanes; 6.86 mL, 17.14 mmol) was added dropwise keeping the temperature below −65° C. The reaction mixture was then stirred at −75° C. for 1 h to ensure complete deprotonation. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3.19 g, 17.14 mmol) was then added to the reaction mixture dropwise keeping the temperature below −65° C. The reaction mixture was then allowed to warm to room temperature, added to diethyl ether (200 mL) and extracted with water (2×100 mL). The aqueous phases were combined and acidified to pH 4 with concentrated HCl. The product was extracted with diethyl ether and the organic phase was dried and concentrated under vacuum to provide the title compound as an off-white solid (3.82 g, 77%): 1H NMR (400 MHz, CDCl3) δ 7.38 (d, J=8.4 Hz, 1H), 7.06 (d, J=8.4 Hz, 1H), 1.36 (s, 12H); EIMS m/z 318.

Source