Reaction #2075716

Reaction equation

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

isopropyl-magnesium chloride

1-Bromo-4-chloro-2,5-difluorobenzene

diethyl ether

→

title compound

Yield 72.3%

2-(4-Chloro-2,5-difluorophenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane

Yield 72.3%

Solvents

THF

THF

tetrahydrofuran

Conditions

Workup

1. 1
   Temperatureto warm toward 0° C. for 1 hour
2. 2
   Temperaturecooled to −10° C. again
3. 3
   Temperatureto warm to ambient temperature
4. 4
   Extractionextracted with 1N sodium hydroxide twice
5. 5
   Extractionextracted with dichloromethane twice
6. 6
   Otherdried
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated

Procedure

1-Bromo-4-chloro-2,5-difluorobenzene (1.11 g, 4.9 mmol) was dissolved in tetrahydrofuran (THF; 15 mL) and cooled to −10° C. A 2.0M solution of isopropyl-magnesium chloride (2.7 mL, 5.4 mmol) in THF was added dropwise via a syringe. The reaction mixture was stirred at −10° C. for 1 hour, allowed to warm toward 0° C. for 1 hour, then cooled to −10° C. again. A solution of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.0 g, 5.4 mmol) in THF (1.0 mL) was then added dropwise and the reaction was allowed to warm to ambient temperature. The reaction mixture was then added to diethyl ether and extracted with 1N sodium hydroxide twice. The aqueous phases were combined, acidified to pH 3 with concentrated HCl, and extracted with dichloromethane twice. The organic phases were combined, dried, filtered and concentrated to give the title compound (0.97 g, 72.3% yield) that was used without further purification: 1H NMR (CDCl3): δ 7.45 (dd, 1H), 7.09 dd, 1H), 1.36 (s, 12H).

Source