Ethylene Glycol → Ethyl 1,4-dioxaspiro(4.5)decane-8-carboxylate

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Reaction Steps

Ethyl 4-oxocyclohexane carboxylate (122.56 mmol, 20.86 g) and para-toluenesulfonic acid monohydrate (12.56 mmol, 2.33 g) are charged to a 1000 mL roundbottom flask. To this flask was added benzene (300 mL) followed by ethylene glycol (0.37 mol, 20.5 mL). The resulting bi-layer reaction mixture was refluxed overnight in a Dean-Stark trap. Upon cooling, the reaction mixture was diluted in 300 mL DCM and washed with 300 mL saturated NaHCO3(aq). The aqueous layer was washed with DCM (3×) and the combined organics are dried over Na2SO4. The residue was dissolved in DCM and purified by silica gel chromatography on 0% to 50% ethyl acetate in hexanes gradient. The product is tracked via PMA stain. Chromatography yields 17.05 grams (79.58 mmol, 65% yield) ethyl 1,4-dioxaspiro[4.5]decane-8-carboxylate.

Provenance & Evidence