Hydrochloric Acid → 3-Tert-butyl-4-methoxyphenylboronic acid

Temperature

-75 °C

To a mixture of 2-(t-butyl)-4-bromoanisole (23.07 g, 0.0949 mol) in THF (238 mL) cooled to −75° C. under an atmosphere of argon was added n-BuLi (65.3 mL, 1.6 M, 0.1044 mol) dropwise maintaining a temperature below −70° C. The resulting suspension was stirred for 30 minutes and triisopropylborate (34.2 mL, 27.87 g, 0.148 mol) was added dropwise. The mixture was allowed to warm to RT overnight. The resulting mixture was cooled to 0° C. and 1.0 N HCl (150 mL) was slowly added. After warming to RT the mixture was diluted with ether and the layers separated, the aqueous layer was extracted ether (3×) and the organic layers combined. The resulting organic layer was washed with water, brine and dried (Mg2SO4). The mixture was filtered, evaporated and the resulting yellowish residue solidified overnight. The solid was collected and washed with hexane and dried under high vacuum to afford 12.68 g of 3-(t-butyl)-4-methoxyphenyl boronic acid (64%). 1H NMR (300 MHz; DMSO-d6): δ 1.33 (s, 9H), 3.81 (s, 3H), 6.91 (d, J=7.8 Hz, 1H), 7.62–7.79 (m, 2H), 7.78 (brs, 2H).

1. temperaturedropwise maintaining a temperature below −70° C
2. temperatureto warm to RT overnight
3. temperatureThe resulting mixture was cooled to 0° C.
4. temperatureAfter warming to RT the mixture
5. customthe layers separated
6. extractionthe aqueous layer was extracted ether (3×)
7. washThe resulting organic layer was washed with water, brine
8. dry with materialdried (Mg2SO4)
9. filtrationThe mixture was filtered
10. customevaporated
11. waitthe resulting yellowish residue solidified overnight
12. customThe solid was collected
13. washwashed with hexane
14. customdried under high vacuum

ORD record

ord-4a981a57bb6e4f708282d560cd362f48

Source dataset

uspto-grants-2006_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07153875B2