Trimethyl borate → 2-Butyloxy-3,5-di-tert-butylphenylboronic acid

온도

-75 °C

2-Butoxy-1,5-di-tert-butyl-3-iodo-benzene (3.88 g, 10 mmol) was dissolved in anhydrous 1,2-dimethoxy-ethane (55 mL under a nitrogen atmosphere. The solution was cooled to −75° C. and t-butyl lithium (14.7 mL, 25 mmol, 1.7M in pentane) was added dropwise over 20-25 min at −72° C. to −69° C. The reaction was stirred at −72° C. for 45 min and then treated with trimethyl borate (5.7 mL, 50 mmol). The reaction was kept cold for 1 h and then the bath was removed and the reaction allowed to warm to room temperature over 24 h. It was treated with 1N hydrochloric acid (35 mL) and stirred for 30 min. The reaction was then diluted with water (200 mL) and extracted with ethyl acetate (150 mL, 2×100 mL). The combined organic portions were washed with bicarbonate solution (100 mL), water (150 mL), brine (150 mL), dried (Na2SO4), filtered and evaporated in vacuo to provide 3.0 g of an oil. The material was purified by flash chromotography (eluet: (9:1) hexane:ethyl acetate and (4:1) hexane:ethyl acetate) to provide 2.04 g (67%) of a white solid. Mp: 82-91° C. 1H NMR (250 MHz, CDCl3): δ 7.66 (d, 1H, J=2.6), 7.48 (d, 1H, J=2.6), 5.75 (s, 1H), 3.84 (t, 2H, J=7.1), 1.84 (m, 2H), 1.47 (m, 2H), 1.42 (s, 9H), 1.33 (s, 9H), 2.66 (t, 3H, J=7.3). MS [EI+] 307 (M+H)+[EI−] 305 (M−H)+.

1. waitThe reaction was kept cold for 1 h
2. customthe bath was removed
3. temperatureto warm to room temperature over 24 h
4. additionIt was treated with 1N hydrochloric acid (35 mL)
5. stirringstirred for 30 min
6. additionThe reaction was then diluted with water (200 mL)
7. extractionextracted with ethyl acetate (150 mL, 2×100 mL)
8. washThe combined organic portions were washed with bicarbonate solution (100 mL), water (150 mL), brine (150 mL)
9. dry with materialdried (Na2SO4)
10. filtrationfiltered
11. customevaporated in vacuo

ORD 기록

ord-f81966e10f8742629ee9a0ddf429811f

출처 데이터셋

uspto-grants-2008_03

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US07348359B2