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

Temperatur

-78 °C

n-Butyllithium (1.55M in hexane) (Aldrich, St. Louis, Mo.; 4.98 mL, 7.72 mmol) was added (dropwise over 5 min) to a solution of 5-(1-(tert-butyldimethylsilyloxy)propan-2-yl)-2-fluoropyridine (1.89 g, 7.01 mmol) in THF (35 mL) at −78° C., and the resulting yellow solution was stirred at −78° C. for 1 h. Triisopropyl borate (Aldrich, St. Louis, Mo.; 1.935 mL, 8.42 mmol) was then added, and the resulting mixture was stirred at −78° C. for 1 h. The reaction mixture was subsequently partitioned between EtOAc (250 mL) and water (90 mL) (1N aq. HCl (12.0 mL) was added to bring the pH to about 6.5). The organic layer was separated, and the aqueous layer was extracted with EtOAc (2×100 mL). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated in vacuo to provide 5-(1-(tert-butyldimethylsilyloxy)propan-2-yl)-2-fluoropyridin-3-ylboronic acid (2.25 g, 7.18 mmol, 102% yield) as a colorless oil, which was used directly in the subsequent step. m/z (ESI, +ve) 314.2 (M+H)+.

1. stirringthe resulting mixture was stirred at −78° C. for 1 h
2. customThe reaction mixture was subsequently partitioned between EtOAc (250 mL) and water (90 mL) (1N aq. HCl (12.0 mL)
3. additionwas added
4. customThe organic layer was separated
5. extractionthe aqueous layer was extracted with EtOAc (2×100 mL)
6. dry with materialThe combined organic extracts were dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo

ORD-Eintrag

ord-fe6e67023a3646298dcaa533868664e0

Quelldatensatz

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08362241B2