Water → Acetic acid, 2-(1,4-dioxaspiro(4.5)dec-8-ylidene)-, ethyl ester

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Reaction Steps

Triethylphosphonoacetate (146 mL, 0.74 mol) is added to a suspension of NaH (60% in oil, 29.5 g, 0.74 mol) in THF (2500 mL) at 0-5° C., and the mixture is stirred for 30 min at the same temperature. To the mixture is added dropwise 1,4-cyclohexanedione monoethylene acetal (100 g, 0.64 mol) in THF (700 mL) at 0-5° C. and stirring is continued for 1 hour at the same temperature. After addition of H2O (1500 mL), the mixture is extracted with EtOAc (3000 mL). The water layer is extracted with EtOAc (1500 mL×2) and combined organic layer is washed with brine, dried over magnesium sulfate, and concentrated under reduced pressure to afford 8-ethoxycarbonylmethylidene-1,4-dioxaspiro[4.5]decane (172.9 g) as a colorless oil. The crude product is used without further purification.

Provenance & Evidence