1,4-dioxaspiro[4.5]decan-9-one

504-02-9

107-21-1

4969-01-1

1. Cyclohexane-1,3-dione (500 g, 4.459 mol), 4A molecular sieves (500 g, 4.459 mol) and p-toluenesulfonic acid (254 g, 1.338 mol) were dissolved in anhydrous ethylene glycol (2 L) under nitrogen protection. 2. The reaction mixture was stirred at room temperature for 4 hours. 3. After completion of the reaction, the reaction mixture was adjusted to an alkaline pH with saturated NaHCO3 solution (1 L). 4. Extract the basic mixture with ethyl acetate (3 × 1 L). 5. 5. The organic phases were combined and washed with brine solution (500 mL) and subsequently dried with Na2SO4. 6. The dried organic phase was filtered and concentrated under reduced pressure to afford 1,4-dioxaspiro[4.5]decan-7-one (280 g, 1.732 mol, 38.8% yield) as a yellow liquid. 7. The product was confirmed by LCMS, m/z 157.1 (M + H+).