Reaction #1833250

Reaction equation

Benzo[d][1,3]dioxole

sec-Butyllithium

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

→

title compound

Yield 34.5%

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

Yield 34.5%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Otherthe temperature below −100° C
2. 2
   Otherthe temperature below −100° C
3. 3
   Temperatureto warm to room temperature
4. 4
   Otherpartitioned between diethyl ether and water
5. 5
   ExtractionThe organic phase was extracted with water once again
6. 6
   ExtractionThe product was extracted with diethyl ether
7. 7
   Otherthe organic phase was dried
8. 8
   Concentrationconcentrated under vacuum
9. 9
   OtherThe product was purified by flash chromatography (silica gel)

Procedure

Benzo[d][1,3]dioxole (3.05 g, 25 mmol) was dissolved in tetrahydrofuran (50 mL) and cooled to −108° C. utilizing a tetrahydrofuran/liquid nitrogen bath. sec-Butyllithium (1.4 M in cyclohexane; 19.64 mL, 27.5 mmol) was added dropwise, keeping the temperature below −100° C. The reaction mixture was then stirred at temperatures between −100° C. and −108° C. for 2 h to ensure complete deprotonation. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4.65 g, 25.00 mmol) was then added to the reaction mixture dropwise, keeping the temperature below −100° C. The reaction mixture was then allowed to warm to room temperature and partitioned between diethyl ether and water. The organic phase was extracted with water once again and the aqueous phases combined and acidified to pH 4 with HCl. The product was extracted with diethyl ether and the organic phase was dried and concentrated under vacuum. The product was purified by flash chromatography (silica gel) to provide the title compound as a white solid (2.14 g, 34.5%): 1H NMR (300 MHz, CDCl3) δ 7.21 (dd, J=7.6, 1.4 Hz, 1H), 6.90 (dd, J=7.7, 1.5 Hz, 1H), 6.82 (t, J=7.6 Hz, 1H), 6.02 (s, 2H), 1.36 (s, 12H); EIMS m/z 248.

Source