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

Participants

Reaction Steps

Ethyl 4-oxocyclohexane carboxylate (122.56 mmol, 20.86 g) and para-toluenesulfonic acid monohydrate (12.56 mmol, 2.33 g) were charged to a 1000 mL round-bottom flask. To this flask was added benzene (300 mL) followed by ethylene glycol (0.37 mol, 20.5 mL). The resulting bi-layer solution was refluxed overnight using a Dean-Stark trap. Upon cooling, the reaction mixture was diluted in 300 mL DCM and washed with 300 mL saturated NaHCO3(aq). DCM was used to extract from the aqueous layer (x3) and the combined organics were dried over Na2SO4. The residue was taken up in DCM and purified by silica gel chromatography using a 0% to 50% ethyl acetate in hexanes gradient. The product was monitored via PMA stain. Chromatography yielded 17.05 grams (79.58 mmol, 65% yield) ethyl 1,4-dioxaspiro[4.5]decane-8-carboxylate (Int-5a).

Provenance & Evidence