تفاعل #2336542

معادلة التفاعل

peracetic acid

1-bromo-4-chloro-2-fluorobenzene

lithium diisopropyl amide

trimethyl borate

→

3-bromo-6-chloro-2-fluorophenol

المردود 63.0%

المذيبات

tetrahydrofuran

THF

Water

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITIONAfter addition the solution
2. 2
   درجة الحرارةcooled to −50° C.
3. 3
   درجة الحرارةthe temperature was warmed to −20° C
4. 4
   درجة الحرارةThe mixture was then cooled to −70° C.
5. 5
   درجة الحرارةthe mixture was warmed to ambient temperature
6. 6
   استخلاصsolution extracted with ethyl acetate (2×200 mL)
7. 7
   أخرىThe combined organic phases were dried
8. 8
   تركيزconcentrated
9. 9
   أخرىThe black oil was purified by column chromatography (20% ethyl acetate in hexanes)

الإجراء التجريبي

A solution of 1-bromo-4-chloro-2-fluorobenzene (20.4 g, 0.100 mol) in tetrahydrofuran (THF; 50 mL) was slowly added to lithium diisopropyl amide (LDA; 0.125 mol) in THF (600 mL) at −50° C. After addition the solution was warmed to −20° C. and then cooled to −50° C. and a solution of trimethyl borate (13.5 g, 0.130 mol) in tetrahydrofuran (20 mL) was added slowly and the temperature was warmed to −20° C. The mixture was then cooled to −70° C. and solution of peracetic acid (32% in acetic acid, 0.150 mol) was slowly added and the mixture was warmed to ambient temperature. Water (250 mL) was added and solution extracted with ethyl acetate (2×200 mL). The combined organic phases were dried and concentrated. The black oil was purified by column chromatography (20% ethyl acetate in hexanes) to give 3-bromo-6-chloro-2-fluorophenol (14.1 g, 0.063 mol): 1H NMR (CDCl3): δ 7.05 (m, 2H), 5.5 (bs, 1H).

المصدر