Reaction #1833249

Reaction equation

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

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

→

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

Yield 84.4%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   workup.ADDITIONIsopropylmagnesium chloride-lithium chloride complex (1.3 M; 10 mL, 13.0 mmol) was added slowly
2. 2
   workup.STIRRINGthe reaction mixture was stirred for 1 h
3. 3
   OtherThe reaction was quenched with saturated aqueous ammonium chloride
4. 4
   Extractionextracted three times with ethyl acetate
5. 5
   WashThe combined organic layers were washed with brine
6. 6
   Dryingdried over anhydrous magnesium sulfate
7. 7
   FiltrationThe solution was filtered
8. 8
   Concentrationconcentrated

Procedure

To an oven-dried three-necked round bottom flask under nitrogen was added 5-bromo-2,2-difluorobenzo[d][1,3]dioxole (2.516 g, 10.6 mmol) and anhydrous tetrahydrofuran (26 mL). The solution was cooled to 0° C. Isopropylmagnesium chloride-lithium chloride complex (1.3 M; 10 mL, 13.0 mmol) was added slowly and stirred for 1 h. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.2 mL, 10.62 mmol) was added, and the reaction mixture was stirred for 1 h. The reaction was quenched with saturated aqueous ammonium chloride and extracted three times with ethyl acetate. The combined organic layers were washed with brine and dried over anhydrous magnesium sulfate. The solution was filtered and concentrated to provide 2-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as a yellow oil (2.54 g, 84%): 1H NMR (400 MHz, CDCl3) δ 7.56 (dd, J=8.0, 1.0 Hz, 1H), 7.47 (d, J=0.6 Hz, 1H), 7.06 (dd, J=7.9, 0.4 Hz, 1H), 1.34 (s, 12H); 19F NMR (376 MHz, CDCl3) δ −50.18; EIMS m/z 284.

Source