Cyclobutanone → Chromanone

Participants

Reaction Steps

2,3-Dimethyl-1,4-phenylene diacetate (5.5 g) was heated up with boron trifluoride-acetic acid complex (25 mL) at 120° C. for 5 hours. The mixture was poured into ice, and extracted with ethyl acetate. The organic layer was washed with sodium bicarbonate water solution to pH about 7. Evaporation gave 5.5 g of 5-acetyl-4-hydroxy-2,3-dimethylphenyl acetate as yellow solid. Refluxing 5-acetyl-4-hydroxy-2,3-dimethylphenyl acetate (5.5 g) with cyclobutanone (1.9 g, 27 mmol) and pyrrolidine (2.1 mL, 24.8 mmol) in toluene failed to give chromanone but gave 3.4 g of 1-(2,5-dihydroxy-3,4-dimethylphenyl)-ethanone as a solid.

Provenance & Evidence