Trimethyl borate → 3-Ethyl-4-fluorophenylboronic acid

To a solution of 95A (290 mg, 1.43 mmol) in THF (5 mL) at −78° C. was added n-BuLi (2.5 M in hexanes, 0.86 mL, 2.15 mmol). The mixture was stirred at −78° C. for 30 min before trimethyl borate (0.32 mL, 2.86 mmol) was added. The reaction was left stirring from −78° C. to rt over 3 h. It was quenched with 1.0 N HCl (2 mL), extracted with EtOAc, washed with Na2S2O3, brine and dried over Na2SO4. After evaporation of the solvent, the crude solid product was purified by silica gel column chromatography eluting with gradient CH2Cl2 in hexanes (0-15%) to give 95B (170 mg, 71% yield). 1H NMR (400 MHz, Methanol-d4) δ ppm 1.09 (t, J=7.47 Hz, 3H) 2.54 (q, J=7.47 Hz, 2H) 6.81-6.88 (m, 1H) 7.42-7.47 (m, 1H) 7.51 (d, J=9.23 Hz, 1H).

1. additionwas added
2. waitThe reaction was left
3. customIt was quenched with 1.0 N HCl (2 mL)
4. extractionextracted with EtOAc
5. washwashed with Na2S2O3, brine
6. dry with materialdried over Na2SO4
7. customAfter evaporation of the solvent
8. customthe crude solid product was purified by silica gel column chromatography
9. washeluting with gradient CH2Cl2 in hexanes (0-15%)

ORD-Eintrag

ord-da0a8c74b4394dd38b69b00a7cded0b2

Quelldatensatz

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08222453B2