反应详情

To a solution of 2-butyryl-3-hydroxy-5-mesitylcyclohex-2-en-1-one (1.20 g) in dichloroethane (20 ml) at 0° C. was added titanium tetrachloride (3.00 g) over a period of 3 minutes. While the solution was stirred and cooled dichloromethyl methyl ether (0.46 g) in dichloroethane (20 ml) was added dropwise over a 25 minute period. After the addition was complete, the mixture was stirred for 5 minutes at 0° C., for 30 minutes at room temperature and for 2 hours under reflux. The cooled reaction mixture was poured into a separatory funnel containing crushed ice and was shaken thoroughly. The organic layer was separated, and the aqeuous solution was extracted with methylene chloride. The combined organic solution was washed with water, dried over anhydrous sodium sulfate and evaporated to dryness to give a crude brown oil (0.70 g). Purification by column chromatography over silica gel (eluant dichloromethane) gave 2-butyryl-3-hydroxy-5-(3-formyl-2,4,6-trimethylphenyl)cyclohex-2-en-1-one (0.35 g) as a pale yellow oil. Proton nuclear magnetic resonance spectrum (CDCl3 ; δ in ppm): 1.0 (3H, t); 1.68 (2H, m); 2.43 (3H, s); 2.48 (3H, s); 2.61 (3H, s); 2.65-4.20 (7H, m); 6.94 (1H, s); 10.54 (1H, s); 18.33 (1H, s).

1. additionwas added dropwise over a 25 minute period
2. additionAfter the addition
3. stirringthe mixture was stirred for 5 minutes at 0° C., for 30 minutes at room temperature and for 2 hours
4. temperatureunder reflux
5. customThe cooled reaction mixture
6. additionwas poured into a separatory funnel
7. additioncontaining
8. customcrushed ice
9. stirringwas shaken thoroughly
10. customThe organic layer was separated
11. extractionthe aqeuous solution was extracted with methylene chloride
12. washThe combined organic solution was washed with water
13. dry with materialdried over anhydrous sodium sulfate
14. customevaporated to dryness
15. customto give a crude brown oil (0.70 g)
16. customPurification by column chromatography over silica gel (eluant dichloromethane)