Diisopropylamine → 2-(2,3-Difluoro-4-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Temperature

-20 °C

A 2.5 M solution of n-butyllithium (3.4 mL, 8.5 mmol) was added to a stirred solution of diisopropylamine (1.2 mL, 8.5 mmol) in THF (25 mL) at −20° C. The resulting solution was stirred at −20° C. for 10 minutes, then cooled to −78° C. A solution of 1,2-difluoro-3-methylbenzene (1.0 g, 7.8 mmol) in THF was added dropwise and stirred at −78° C. for 2 h. 2-Isopropoxy-4,4,5,5-tetramethyl[1,3,2]dioxaborolane (1.6 g, 8.6 mmol) in THF was then added and the brown solution was slowly warmed to 23° C. over 16 hours. The reaction mixture was then added to ether and extracted with water and with 0.1N sodium hydroxide. The combined aqueous extracts were acidified with concentrated HCl then extracted with dichloromethane. The organic phase was dried and concentrated to give the title compound (1.0 g, 50% yield): 1H NMR (CDCl3): δ 7.32 (m, 1H), 6.92 (m, 1H), 2.31 (s, 3H), 1.32 (s, 12H).

1. temperaturecooled to −78° C
2. stirringstirred at −78° C. for 2 h
3. temperaturethe brown solution was slowly warmed to 23° C. over 16 hours
4. extractionextracted with water and with 0.1N sodium hydroxide
5. extractionthen extracted with dichloromethane
6. customThe organic phase was dried
7. concentrationconcentrated

ORD record

ord-d7e5ea6c8d7d4005af89a5aac39c8538

Source dataset

uspto-grants-2011_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07915200B2