Bromine → 3-Bromo-2-hydroxy-cyclohex-1-enecarboxylic acid ethyl ester
Reaction equation
[O:1]=[C:2]1[CH2:7][CH2:6][CH2:5][CH2:4][CH:3]1[C:8]([O:10][CH2:11][CH3:12])=[O:9].[Br:13]Br>C(OCC)C>[CH2:11]([O:10][C:8]([C:3]1[CH2:4][CH2:5][CH2:6][CH:7]([Br:13])[C:2]=1[OH:1])=[O:9])[CH3:12]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
Ethyl 2-oxocyclohexanecarboxylate (5.0 g, 29 mmol, 4.7 mL) was dissolved in diethyl ether (5 mL) and cooled to 0° C. under N2. Bromine (4.6 g, 29 mmol, 4.2 mL) was added dropwise over 15 min and the reaction mixture was allowed to warm to room temperature over 90 min. The mixture was slowly poured into ice-cold saturated aqueous sodium carbonate solution (40 mL) and extracted with ethyl acetate (3×40 mL). The combined organic layers were dried and concentrated in vacuo to afford 5.96 g (81%) of 3-bromo-2-hydroxy-cyclohex-1-enecarboxylic acid ethyl ester (29) as a pale yellow oil which was used in the next step without purification. The structure was confirmed by 13C NMR (75 MHz, DMSO-d6) δC 14.14, 17.65, 21.77, 32.02, 59.95, 60.83, 99.70, 166.33, 172.81.