Reaction #1833244

Reaction equation

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

4-Bromo-2,2,7-trifluorobenzo[d][1,3]dioxole

HCl

NH4Cl

→

title compound

Yield 98.0%

4,4,5,5-Tetramethyl-2-(2,2,7-trifluorobenzo[d][1,3]dioxol-4-yl)-1,3,2-dioxaborolane

Yield 98.0%

Solvents

tetrahydrofuran

ethyl acetate

Conditions

Workup

1. 1
   workup.ADDITIONtreated in portions with isopropylmagnesium lithium chloride complex (1.3 M; 6.3 mL, 8.2 mmol)
2. 2
   workup.STIRRINGstirred for 2 h at 10 to 20° C
3. 3
   workup.STIRRINGstirred for 10 min
4. 4
   WashThe organic phase was washed with saturated NaCl (10 mL)
5. 5
   Dryingdried (Na2SO4)
6. 6
   Otherevaporated

Procedure

4-Bromo-2,2,7-trifluorobenzo[d][1,3]dioxole (2.0 g, 7.8 mmol) was dissolved in dry tetrahydrofuran (12 ml), cooled to −5° C. and treated in portions with isopropylmagnesium lithium chloride complex (1.3 M; 6.3 mL, 8.2 mmol). The mixture was stirred for 2 h at 5 to 15° C., treated with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.6 g, 8.4 mmol) and stirred for 2 h at 10 to 20° C. The mixture was treated with saturated NH4Cl (5 mL), stirred for 10 min and then shaken with 1 M HCl (10 mL) and ethyl acetate (75 mL). The organic phase was washed with saturated NaCl (10 mL), dried (Na2SO4) and evaporated to give the title compound as a white solid (2.3 g, 98%): 1H NMR (400 MHz, CDCl3) δ 7.41 (dd, J=8.7, 5.3 Hz, 1H), 6.88 (dd, J=9.5, 8.8 Hz, 1H), 1.36 (s, 12H); 19F NMR (376 MHz, CDCl3) δ −49.07, −131.31; EIMS m/z 302.

Source