Triisopropyl borate → 2-((4-(2-Methoxyethoxy)phenoxy)methyl)-4-chlorophenylboronic acid
Reaction equation
Br[C:2]1[CH:20]=[CH:19][C:18]([Cl:21])=[CH:17][C:3]=1[CH2:4][O:5][C:6]1[CH:11]=[CH:10][C:9]([O:12][CH2:13][CH2:14][O:15][CH3:16])=[CH:8][CH:7]=1.[B:22](OC(C)C)([O:27]C(C)C)[O:23]C(C)C.[Li]CCCC>C1COCC1>[CH3:16][O:15][CH2:14][CH2:13][O:12][C:9]1[CH:10]=[CH:11][C:6]([O:5][CH2:4][C:3]2[CH:17]=[C:18]([Cl:21])[CH:19]=[CH:20][C:2]=2[B:22]([OH:27])[OH:23])=[CH:7][CH:8]=1Participants
Conditions
- Temperature
- -78 °C
Procedure
In a flask, 1.8 g (4.8 mmol) of the compound obtained in Step 2 was dissolved in 10 ml of anhydrous THF, and 1.34 ml (5.8 mmol) of triisopropyl borate was added thereto. The flask was cooled to −78° C. over a dry ice-acetone bath, 2.3 ml (5.8 mmol) of 2.5 M n-BuLi (in hexane) was added dropwise to the mixture over 15 min. After the reaction mixture was kept for 1 hour, the dry ice-acetone bath was removed, and 5 ml of 2 N HCl was added to the mixture. After stirring the mixture for 1 hour, the water layer was separated and extracted twice with 10 ml portions of ethyl acetate. The organic layers were combined, washed with a brine solution, dried over anhydrous MgSO4, and filtered under a reduced pressure to remove the solvent. The residue was recrystallized from ethyl acetate/hexane to obtain 1.12 g (yield 69%) of 2-((4-(2-methoxyethoxy)phenoxy)methyl)-4-chlorophenylboronic acid.
Workup
- customthe dry ice-acetone bath was removed
- addition5 ml of 2 N HCl was added to the mixture
- customthe water layer was separated
- extractionextracted twice with 10 ml portions of ethyl acetate
- washwashed with a brine solution
- dry with materialdried over anhydrous MgSO4
- filtrationfiltered under a reduced pressure
- customto remove the solvent
- customThe residue was recrystallized from ethyl acetate/hexane
Sources & evidence
- ORD record
- ord-bf47da197d2b407ab1ce8b4d897881d0
- Source dataset
- uspto-grants-2012_07
- Patent number
- US08227456B2
Reaction notes
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