反应详情

Into a reaction vessel, a solution of 4-hydroxy-4-methyl-5-allyl-2-cyclopentenone (3 g) and ZnCl2 (5 g) in water (120 ml) was charged, and the temperature was elevated up to 100° C. The contents were refluxed for 15 hours while stirring. After cooling, NaCl (40 g) was added to the reaction mixture, and the resulting mixture was extracted with toluene (120 ml) 4 times. The extracts were combined together and concentrated at 50° C. under reduced pressure to give an oily substance (2.5 g). The oily substance was chromatographed on silica gel (30 g), followed by development with a solvent mixture of ethyl acetate and hexane (1:2 by volume) to give 2-allyl-3-methyl-4-hydroxy-2cyclopentenone (2.4 g). Yield, 80%.

1. customwas elevated up to 100° C
2. temperatureThe contents were refluxed for 15 hours
3. temperatureAfter cooling
4. extractionthe resulting mixture was extracted with toluene (120 ml) 4 times
5. concentrationconcentrated at 50° C. under reduced pressure
6. customto give an oily substance (2.5 g)
7. customThe oily substance was chromatographed on silica gel (30 g)
8. additionfollowed by development with a solvent mixture of ethyl acetate and hexane (1:2 by volume)