Trimethyl borate → 3,3-diethyl-5-methylbenzo[c][1,2]oxaborol-1(3H)-ol

To a solution of 3-(2-bromo-5-methylphenyl)pentan-3-ol (6.5 g, 25.2 mmol) in THF (150 ml) at −78° C. was slowly added n-BuLi (30.24 ml, 75.6 mmol). The reaction mixture was warmed to rt and stirred for 2 h. After being cooled to −78° C., trimethyl borate (5.23 g, 50.4 mmol) was added dropwise and the reaction mixture was warmed to rt, stirred for 10 h under nitrogen and quenched with 2N HCl (50 ml). The mixture was extracted with EA (40 ml×3). The combined organic layers were washed with water and brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE:EA (10:1 to 1:1) to give the product (2.0 g, yield 38.9%) as a white solid. 1H NMR (300 MHz, DMSO-d6): δ 8.87 (s, 1H), 7.52-7.47 (d, 1H), 7.11-7.06 (m, 2H), 2.35 (s, 3H), 1.88-1.68 (m, 4H), 0.60-0.45 (m, 6H). MS: m/z=205 [M+1]+.

1. customat −78° C.
2. temperatureAfter being cooled to −78° C.
3. temperaturethe reaction mixture was warmed to rt
4. stirringstirred for 10 h under nitrogen
5. customquenched with 2N HCl (50 ml)
6. extractionThe mixture was extracted with EA (40 ml×3)
7. washThe combined organic layers were washed with water and brine
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure
11. customThe residue was purified by column chromatography over silica gel
12. washeluted with PE

ORD record

ord-0eed6d4bd5c54c53996ffb11753c4c32

Source dataset

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08853186B2