Triisopropyl borate → 5-(1-(Tert-butyldimethylsilyloxy)-2-methylpropan-2-yl)-2-fluoropyridin-3-ylboronic acid

Temperatur

-78 °C

n-Butyllithium (1.66 M in hexane) (Aldrich, St. Louis, Mo.; 0.429 mL, 0.712 mmol) was added (dropwise over 1 min) to a solution of 5-(1-(tert-butyldimethylsilyloxy)-2-methylpropan-2-yl)-2-fluoropyridine (183.5 mg, 0.647 mmol) in THF (3.3 mL) at −78° C., and the resulting yellow solution was stirred at −78° C. for 1 h. Tri-isopropyl borate (Aldrich, St. Louis, Mo.; 0.179 mL, 0.777 mmol) was then added, and the resulting mixture was stirred at −78° C. for 1 h. The reaction mixture was subsequently partitioned between EtOAc (50 mL) and water (30 mL) (1N HCl (about 200 μL) was added to bring the pH of the aqueous layer to 6.5). The organic layer was separated, and the aqueous layer was extracted with EtOAc (30 mL). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated in vacuo to provide 5-(1-(tert-butyldimethylsilyloxy)-2-methylpropan-2-yl)-2-fluoropyridin-3-ylboronic acid (228.0 mg, 0.697 mmol, 108% yield) as a colorless oil. m/z (ESI, +ve) 328.3 (M+H)+.

1. stirringthe resulting mixture was stirred at −78° C. for 1 h
2. customThe reaction mixture was subsequently partitioned between EtOAc (50 mL) and water (30 mL) (1N HCl (about 200 μL)
3. additionwas added
4. customThe organic layer was separated
5. extractionthe aqueous layer was extracted with EtOAc (30 mL)
6. dry with materialThe combined organic extracts were dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo

ORD-Eintrag

ord-c3b398b82fe64ffeafbde30457bba527

Quelldatensatz

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08362241B2