반응 #56871

반응 방정식

hydrochloric acid

2-methyl-5-bromo-iodobenzene

isopropylmagnesium chloride

trimethylborate

→

2-methyl-5-bromo-phenylboronic acid

수율 84.3%

용매

tetrahydrofuran

tetrahydrofuran

반응 조건

후처리

1. 1
   온도the mixture was warmed slowly to −20° C.
2. 2
   workup.STIRRINGstirred for 1 hour
3. 3
   온도After cooling again to −78° C.
4. 4
   온도After warming to 0° C.
5. 5
   workup.STIRRINGthe mixture was stirred for 2 hours
6. 6
   추출extracted with ethyl acetate (2×50 ml)
7. 7
   세척The combined extracts were washed with water (50 ml)
8. 8
   건조dried over sodium sulfate
9. 9
   농축concentrated under reduced pressure
10. 10
    여과filtered
11. 11
    세척washed with hexane (30 ml)
12. 12
    기타dried under reduced pressure

실험 절차

To a solution of 2-methyl-5-bromo-iodobenzene (12 g, 40.4 mmol) in tetrahydrofuran (75 ml), cooled to −78° C., was added a solution of isopropylmagnesium chloride (4.6 g, 44.5 mmol) in tetrahydrofuran (22.2 ml) dropwise over 20 minutes. After stirring at −78° C. for 30 minutes, the mixture was warmed slowly to −20° C. and stirred for 1 hour. After cooling again to −78° C., trimethylborate (8.4 g, 80.8 mmol) was added dropwise. After warming to 0° C., the mixture was stirred for 2 hours, treated with 1 M hydrochloric acid (35 ml), and extracted with ethyl acetate (2×50 ml). The combined extracts were washed with water (50 ml), dried over sodium sulfate, and concentrated under reduced pressure. The residual solid was suspended in hexane (50 ml), filtered, washed with hexane (30 ml) and dried under reduced pressure to provide 2-methyl-5-bromo-phenylboronic acid (7.32 g, 84% yield) as a white solid. 1H NMR (DMSO-d6) δ 7.92 (s, 1H), 7.46 (d, J=8.1 Hz, 1H), 7.13 (d, J=8.1 Hz, 1H), 2.59 (s, 3H).

출처