Ethanol → (1R,2R)-ethyl 2-(4-hydroxyphenyl)cyclopropanecarboxylate
Reaction equation
[CH2:1]([O:3][C:4]([C@@H:6]1[CH2:8][C@H:7]1[C:9]1[CH:14]=[CH:13][C:12]([O:15]C)=[CH:11][CH:10]=1)=[O:5])[CH3:2].B(Br)(Br)Br.C(O)C>ClCCl.C(=O)(O)[O-].[Na+]>[CH2:1]([O:3][C:4]([C@@H:6]1[CH2:8][C@H:7]1[C:9]1[CH:10]=[CH:11][C:12]([OH:15])=[CH:13][CH:14]=1)=[O:5])[CH3:2]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- -78 °C
Procedure
2-(4-Methoxy-phenyl)-trans-cyclopropanecarboxylic acid ethyl ester (1.43 g, 6.51 mmol) is dissolved in dry dichloromethane (30 mL) and cooled to −78° C. Boron tribromide solution (1 M in dichloromethane, 7.81 mL, 7.81 mmol) is added dropwise then the mixture is allowed to warm to −20° C. and stirred overnight at −20° C. Ethanol (3 mL) is added and the mixture warmed to room temperature then diluted with saturated aqueous sodium bicarbonate solution. The phases are separated and the aqueous phase extracted with dichloromethane. The combined organic phases are dried through a phase separator and the solvent removed under vacuum. The residue is purified by flash chromatography (10% ethyl acetate in cyclohexane) and then crystallized from 10% ethyl acetate in cyclohexane to give the title compound (yield 0.58 g). LC (METHOD 11): tR=6.25 min; Mass spectrum (ESI+): m/z=248 [M+H+MeCN]+.
Workup
- temperatureto warm to −20° C.
- temperaturethe mixture warmed to room temperature
- customThe phases are separated
- extractionthe aqueous phase extracted with dichloromethane
- customThe combined organic phases are dried through a phase separator
- customthe solvent removed under vacuum
- customThe residue is purified by flash chromatography (10% ethyl acetate in cyclohexane)
- customcrystallized from 10% ethyl acetate in cyclohexane
Sources & evidence
- ORD record
- ord-4f6af052fac2458eacd2d86195962001
- Source dataset
- uspto-grants-2016_04
- Patent number
- US09308194B2
Reaction notes
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