Triisopropyl borate → (5-Methoxy-1-benzofuran-2-yl)boronic acid

Temperature

-78 °C

n-Butyllithium 2.5M in hexanes (5.6 mL) was added slowly to a solution of 5-methoxybenzofuran (13.5 mmol) in dry THF (30 mL) at −78° C. After 1 h stirring at −78° C., triisopropylborate (27.0 mmol) was added dropwise and the mixture was stirred for another 20 min at −78° C. The dry ice bath was removed and HCl 2N (aq. 40 mL) was added and the mixture allowed to warm to r.t. and then poured in water (50 mL). The resulting aqueous solution was extracted with ether, the organic layer was washed with brine, dried over MgSO4, filtered and concentrated under vacuum to afford the title compound as a beige powder (2.40 g). 1H NMR δ ppm 8.49 (s, 2 H) 7.45 (d, 1 H) 7.38 (s, 1 H) 7.18 (d, 1 H) 6.93 (dd, 1 H) 3.78 (s, 3 H).

1. stirringthe mixture was stirred for another 20 min at −78° C
2. customThe dry ice bath was removed
3. additionHCl 2N (aq. 40 mL) was added
4. temperatureto warm to r.t.
5. additionpoured in water (50 mL)
6. extractionThe resulting aqueous solution was extracted with ether
7. washthe organic layer was washed with brine
8. dry with materialdried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated under vacuum

ORD record

ord-712ebf5fd84d48ab833337dcf6d23b09

Source dataset

uspto-grants-2010_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07772256B2