Sulfuric Acid → Spiro[5.5]undec-1-en-3-one

Participants

Reaction Steps

To a solution of cyclohexanecarbaldehyde (10.7 mL) in toluene (100 mL) were added successively methyl vinyl ketone (15 mL) and concentrated sulfuric acid (0.1 mL). The reaction mixture was stirred at room temperature for 1 hour and then heated under reflux while stirring for 4 hours. After cooling down to room temperature, saturated aqueous sodium bicarbonate solution was added to the reaction mixture, followed by separation of the organic layer. Then, after the aqueous layer was extracted with toluene, the organic layers were combined, washed with saturated brine, dried and concentrated. The residue was purified by column chromatography on silica gel (ethyl acetate:hexane (volume ratio)=1:20 to 1:12) to give spiro[5.5]undec-1-en-3-one (8.9 g).

Provenance & Evidence