Diethyl Ether → 8-Chloro-7-isopropoxy-4-isopropyl-2,2-dimethyl-2H-chromene-6-carbaldehyde
Reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:9](=[C:10]([Cl:16])[C:11]=1[O:12][CH:13]([CH3:15])[CH3:14])[O:8][C:7]([CH3:18])([CH3:17])[CH:6]=[C:5]2[CH:19]([CH3:21])[CH3:20].C([Li])CCC.[CH2:27]([O:29]CC)C>>[Cl:16][C:10]1[C:11]([O:12][CH:13]([CH3:15])[CH3:14])=[C:2]([CH:27]=[O:29])[CH:3]=[C:4]2[C:9]=1[O:8][C:7]([CH3:18])([CH3:17])[CH:6]=[C:5]2[CH:19]([CH3:21])[CH3:20]Participants
Conditions
- Temperature
- -78 °C
Procedure
To a solution of 6-bromo-8-chloro-7-isopropoxy-4-isopropyl-2,2-dimethyl-2H-chromene, (Compound 21, 3.9 g, 10.3 mmol) in diethyl ether (100 mL) at −78° C. was added n-butyllithium (1.6 M in hexanes, 10.3 mL, 16.5 mmol). After stirring at −78° C. for 20 min, the reaction mixture was quenched with DMF (10 mL). After further stirring at −78° C. for 15 min, the reaction was allowed to warm to room temperature. The reaction mixture was poured into 1N HCl and extracted with ethyl acetate. The combined organic layers were washed with water and brine, dried (MgSO4), filtered, and concentrated under reduced pressure. The crude residue was purified by flash chromatography (silica gel, 100% hexanes to 2% ethyl acetate in hexanes) to afford the title compound as a colorless oil.
Workup
- customthe reaction mixture was quenched with DMF (10 mL)
- stirringAfter further stirring at −78° C. for 15 min
- temperatureto warm to room temperature
- additionThe reaction mixture was poured into 1N HCl
- extractionextracted with ethyl acetate
- washThe combined organic layers were washed with water and brine
- dry with materialdried (MgSO4)
- filtrationfiltered
- concentrationconcentrated under reduced pressure
- customThe crude residue was purified by flash chromatography (silica gel, 100% hexanes to 2% ethyl acetate in hexanes)
Sources & evidence
- ORD record
- ord-c814c10568e045ec9060f7061c454a38
- Source dataset
- uspto-grants-2005_05
- Patent number
- US06887896B1
Reaction notes
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