4746-97-8

22428-87-1

Step A: Preparation of 4-dioxaspiro[4.5]decan-8-ol 1,4-Cyclohexanedione monoethylene glycol ketal (5.0134 g, 32.10 mmol) was dissolved in methanol (100 mL) and cooled in an ice bath. Sodium borohydride (3.64 g, 96.30 mmol) was added to the solution in batches over 20 min. The reaction mixture was stirred at 0 °C for 30 min, then slowly warmed to room temperature and continued stirring for 1 h. The reaction mixture was then stirred at 0 °C for 1 h. The reaction mixture was then stirred at 0 °C for 1 h. Upon completion of the reaction, 4-hydroxycyclohexanone ethylene glycol acetal (5.56 g, 109% yield) was obtained by a standard post-processing step, the product was a yellow oil and could be used in subsequent reactions without further purification. The structure of the product was confirmed by 1H NMR (400 MHz, chloroform-D): δ 1.47-1.70 (m, 5H), 1.72-1.92 (m, 4H), 3.70-3.83 (m, 1H), 3.85-3.96 (m, 4H).