Reaction #1833220

Reaction equation

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

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

→

title compound

Yield 101.8%

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

Yield 101.8%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   workup.ADDITIONtreated in portions with isopropylmagnesium chloride-lithium chloride complex solution (1.3 M; 3.1 mL, 4.1 mmol)
2. 2
   workup.WAITwas continued at 0-20° C. for 90 min
3. 3
   OtherThe reaction was quenched by addition of saturated NH4Cl (10 mL)
4. 4
   Extractionthe mixture was extracted with ethyl acetate (30 mL)
5. 5
   ExtractionThe aqueous phase was extracted again with ethyl acetate (15 mL)
6. 6
   Washthe combined organic phases were washed with saturated NaCl (15 mL)
7. 7
   Dryingdried (Na2SO4)
8. 8
   Otherevaporated

Procedure

5-Bromo-4-chloro-2,2-difluorobenzo[d][1,3]dioxole (1.0 g, 3.7 mmol) was dissolved in dry tetrahydrofuran (12 mL), cooled to −20 to −30° C. and treated in portions with isopropylmagnesium chloride-lithium chloride complex solution (1.3 M; 3.1 mL, 4.1 mmol). After 90 min at −20 to 0° C., 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (830 μL, 750 mg, 4.1 mmol) was added, and stirring was continued at 0-20° C. for 90 min. The reaction was quenched by addition of saturated NH4Cl (10 mL), and the mixture was extracted with ethyl acetate (30 mL). The aqueous phase was extracted again with ethyl acetate (15 mL), and the combined organic phases were washed with saturated NaCl (15 mL), dried (Na2SO4) and evaporated to give the title compound as a white solid (1.2 g, ca. 100%): 1H NMR (400 MHz, CDCl3) δ 7.52 (d, J=8.1 Hz, 1H), 6.99-6.94 (m, 1H), 1.36 (s, 12H); 19F NMR (376 MHz, CDCl3) δ −49.62 (s); EIMS m/z 318.

Source