Ethylene Glycol → Methyl 1,4-dioxaspiro[4.4]nonane-6-carboxylate

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Reaction Steps

A reflux condenser equipped with a Dean-Stark water separator was attached to a round bottom flask containing methyl 2-cyclopentanonecarboxylate (2 ml, 16.2 mmol), ethylene glycol (994 μl, 17.8 mmol), p-toluenesulfonic acid monohydrate (139 mg, 0.73 mmol), and benzene (30 ml). The mixture was heated under reflux for 2 hours. To the reaction mixture, triethylamine (0.22 ml) was added and the mixture was concentrated and purified by silica gel column chromatography (elution solvent: ethyl acetate/heptane=1/9, 1/1) to obtain the title compound (2.12 g, yield 70.3%) as a colorless oil.

Provenance & Evidence