Triisopropyl borate → 5-(1-Phenylethyl)benzofuran-2-ylboronic acid

To a solution of 5-(1-phenylethyl)benzofuran (0.713 g, 3.21 mmol) in 32 mL THF at −78° C. was added 1-butyllithium (1.54 mL, 3.85 mmol) slowly dropwise. The reaction was allowed to stir for 25 min, at which point triisopropyl borate (1.08 mL, 4.72 mmol) was added slowly dropwise. After 0.5 h, the bath was removed and the reaction was allowed to warm to ambient temperature. After 0.5 h, 50 mL 2N HCl was added. The mixture was extracted 2×MTBE, and the combined organics were washed with brine, dried over anhyd. sodium sulfate, filtered, and concentrated in vacuo to give an oil. Treatment with 30 mL hexanes and sonication for 5 min resulted in a white solid which was collected by filtration and dried in vacuo to give 5-(1-phenylethyl)benzofuran-2-ylboronic acid. 1H NMR (400 MHz, DMSO-d6) δ ppm 8.49-8.57 (m, 2H), 7.58 (s, 1H), 7.46 (d, J=8.5 Hz, 1H), 7.40 (s, 1H), 7.12-7.32 (m, 6H), 4.26 (q, J=7.5 Hz, 1H), 1.62 (d, J=7.0 Hz, 3H).

1. additionwas added slowly dropwise
2. customthe bath was removed
3. waitAfter 0.5 h
4. addition50 mL 2N HCl was added
5. extractionThe mixture was extracted 2×MTBE
6. washthe combined organics were washed with brine
7. customdried over anhyd
8. filtrationsodium sulfate, filtered
9. concentrationconcentrated in vacuo
10. customto give an oil
11. customresulted in a white solid which
12. filtrationwas collected by filtration
13. customdried in vacuo

ORD record

ord-9e97cc710d584e8297e1024463256ce2

Source dataset

uspto-grants-2011_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07919519B2