Reaction #1833239

Reaction equation

NH4Cl

6-Bromo-4-methoxybenzo[d][1,3]dioxole

isopropylmagnesium lithium chloride

HCl

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

→

title compound

Yield 33.2%

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

Yield 33.2%

Solvents

ethyl acetate

tetrahydrofuran

Conditions

Workup

1. 1
   Temperaturethe temperature was raised to 40° C.
2. 2
   TemperatureThe mixture was cooled to 20° C.
3. 3
   workup.STIRRINGstirred for 3 h
4. 4
   workup.STIRRINGwas stirred for 10 min
5. 5
   WashThe organic phase was washed with saturated NaCl (10 mL)
6. 6
   Dryingdried (Na2SO4)
7. 7
   Otherevaporated
8. 8
   OtherThe product was purified by flash chromatography with dichloromethane

Procedure

6-Bromo-4-methoxybenzo[d][1,3]dioxole (1.5 g, 6.5 mmol, prepared according to Shirasaka, Tadashi; Takuma, Yuki; Imaki, Naoshi. Synthetic Communications 1990, 20, 1223-1232) was dissolved in dry tetrahydrofuran (25 mL), cooled to 5° C. and treated with isopropylmagnesium lithium chloride (1.3 M; 5.2 mL, 6.8 mmol). After 50 min at 10° C., the temperature was raised to 40° C. and stirred for 5 h. The mixture was cooled to 20° C., treated with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.3 g, 7.1 mmol) and stirred for 3 h. The mixture was treated with saturated NH4Cl (2 mL), followed by 1 M HCl (8 mL) and ethyl acetate (20 mL), and then was stirred for 10 min. The organic phase was washed with saturated NaCl (10 mL), dried (Na2SO4) and evaporated. The product was purified by flash chromatography with dichloromethane to give the title compound as a white solid (600 mg; 33%): mp 86-88° C.; 1H NMR (400 MHz, CDCl3) δ 7.01 (d, J=0.5 Hz, 1H), 6.97 (d, J=0.8 Hz, 1H), 5.98 (s, 2H), 3.93 (s, 4H), 1.33 (s, 12H); EIMS m/z 278.

Source