تفاعل #1071939

معادلة التفاعل

trimethylborate

2-octyl-5-bromobenzofuran

n-butyllithium

hydrochloric acid

→

2-octylbenzofuran-5-boronic acid

المردود 64.1%

المذيبات

THF

tetrahydrofuran

hexane

ظروف التفاعل

المعالجة

1. 1
   workup.STIRRINGstirred at that temperature for 2 hours
2. 2
   workup.STIRRINGstirred for 17 hours
3. 3
   استخلاصfollowed by extraction with ether
4. 4
   غسيلThe organic layer was washed with water
5. 5
   تجفيفdried with anhydrous sodium sulfate
6. 6
   أخرىto obtain a residue
7. 7
   أخرىThe residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=4/1)

الإجراء التجريبي

In a 500 ml-three-necked flask, 19.0 g (61.5 mM) of 2-octyl-5-bromobenzofuran (II) and 190 ml of anhydrous tetrahydrofuran (THF) were placed. To the mixture, 45 ml (72.0 mM) of 1.6M-n-butyllithium solution in hexane was added dropwise under argon stream at −70° C. or below in 30 min., followed by stirring at that temperature for 4 hours. To the resultant mixture, a solution of 17.8 g (171 mM) of trimethylborate in 70 ml of anhydrous THF was added dropwise at −70° C. or below in 20 min., and stirred at that temperature for 2 hours. The system was heated up to room temperature and stirred for 17 hours. To the reaction mixture, 100 ml of 10%-hydrochloric acid was added dropwise, followed by extraction with ether. The organic layer was washed with water and dried with anhydrous sodium sulfate, followed by distilling-off of the solvent under reduced pressure to obtain a residue. The residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=4/1) to obtain a white crystal of 2-octylbenzofuran-5-boronic acid (III) (Yield: 10.8 g (64.1%)).

المصدر