反应详情

温度

110 °C

To a of solution cis-tetrahydropentalene-2,5-(1H,3H)-dione (2.99 g, 21.6 mmol) and 2,2-dimethylpropane-1,3-diol (2.254 g, 21.6 mmol) in toluene (70 mL) was added p-toluenesulfonic acid monohydrate (0.206 g, 1.08 mmol) and the mixture was heated at 110° C. for 24 hrs with a Dean Stark apparatus. The reaction mixture was cooled to room temperature, poured over solid K2CO3, stirred 5 mins then filtered and concentrated under reduced pressure. The residue was purified by flash chromatography (12 to 100% EtOAc in hexanes) to give 5,5-dimethyltetrahydro-1′H-spiro[1,3-dioxane-2,2′-pentalen]-5′(3′H)-one (2.224 g, 9.92 mmol, 45.8% yield) as a colorless oil which solidified upon standing. MS ESI: [M+Na]+ m/z 225.7.

1. temperatureThe reaction mixture was cooled to room temperature
2. filtrationthen filtered
3. concentrationconcentrated under reduced pressure
4. customThe residue was purified by flash chromatography (12 to 100% EtOAc in hexanes)