反应详情

To a solution of 1-bromo-4-isopropyl-2-methoxy-benzene and 1-bromo-2-isopropyl-4-methoxy-benzene from step 2 (6.621 g, 28.9 mmol) in 100 mL 1,2 dichloroethane was added TiCl4 (6.3 mL, 57.8 mmol) at 0° C. After 10 minutes, dichloromethoxymethane (Cl2CHOMe) (2.6 mL, 28.9 mmol) was added and the mixture was warmed to reflux. After 3 hours the mixture was cooled poured over ice and acidified with 50 mL 2 M HCl. The resulting slurry was extracted with CH2Cl2, and washed with brine. The combined organics were dried over MgSO4, filtered and concentrated in vacuo to give a dark-green oil. Purification via flash chromatography (96:4 hexane/ethyl acetate) afforded 5-bromo-2-isopropyl-4-methoxy-benzaldehyde and 5-bromo-4-isopropyl-2-methoxy-benzaldehyde (2.876 g, 39%, 6.621 g, 72%) as a 1:1 mixture of inseparable isomers in the form of an orange oil, which was used directly in step 4.

1. temperaturethe mixture was warmed to reflux
2. temperatureAfter 3 hours the mixture was cooled
3. additionpoured over ice
4. extractionThe resulting slurry was extracted with CH2Cl2
5. washwashed with brine
6. dry with materialThe combined organics were dried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customto give a dark-green oil
10. customPurification via flash chromatography (96:4 hexane/ethyl acetate)