Reaktion #1833222

Reaktionsgleichung

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

isopropylmagnesium chloride lithium chloride

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

→

title compound

Ausbeute 72.4%

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

Ausbeute 72.4%

Lösungsmittel

tetrahydrofuran

NH4Cl

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITwas continued for 1 h at 10-15° C
3. 3
   WaschenThe organic phase was washed with saturated NaCl (15 mL)
4. 4
   Trocknendried (Na2SO4)
5. 5
   Sonstigeevaporated

Vorschrift

5-Bromo-2,2,4-trifluorobenzo[d][1,3]dioxole (4.0 g, 16 mmol) was dissolved in 20 mL dry tetrahydrofuran, cooled to −20° C. and treated with isopropylmagnesium chloride-lithium chloride complex (1.3 M in tetrahydrofuran; 13 mL, 17 mmol) in portions over 10 min. After stirring for 30 min at −20 to 0° C., 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3.1 g, 17 mmol) was added, and stirring was continued for 1 h at 10-15° C. After treatment with saturated NH4Cl solution (10 mL), the mixture was diluted with ethyl acetate (50 mL). The organic phase was washed with saturated NaCl (15 mL), dried (Na2SO4) and evaporated to give the title compound as a brown solid (3.5 g, 72%): 1H NMR (400 MHz, CDCl3) δ 7.46 (d, J=26.5 Hz, 1H), 6.90 (dd, J=18.5, 4.5 Hz, 1H), 1.35 (s, 12H); 19F NMR (376 MHz, CDCl3) δ −49.70 (s), −126.00 (s); EIMS m/z 302.

Quelle