Dimethyl Carbonate → 1-Oxo-spiro[5.5]undecane-2-carboxylic acid methyl ester

Participants

Reaction Steps

To a suspension of 60% sodium hydride (5.7 g) and potassium tert-butoxide (1.6 g) in tetrahydrofuran (200 mL) was added dimethyl carbonate (9.6 mL) at room temperature while stirring. The reaction mixture was heated under reflux. To the reaction mixture was added dropwise a solution of spiro[5.5]undecan-1-one (11.85 g) obtained in Step 1 in tetrahydrofuran (40 mL) over 1 hour, followed by heating the reaction mixture under reflux for 2 hours. After ice-cooling, acetic acid (14.6 mL) was added dropwise to the reaction mixture. Then, the reaction mixture was poured into saturated brine, followed by extraction with ethyl acetate. The organic layer was washed with saturated brine, dried and concentrated. The residue was purified by column chromatography on silica gel (ethyl acetate:hexane (volume ratio)=1:15) to give 1-oxo-spiro[5.5]undecane-2-carboxylic acid methyl ester (13.02 g).

Provenance & Evidence