Water → 3-Oxaspiro[5.5]undec-7-en-9-one

Participants

Reaction Steps

5.00 g (43.8 mmol) tetrahydropyran-4-carboxaldehyde and 3.56 ml (43.9 mmol) methylvinylketone were boiled in 70 ml of toluene with 0.07 ml conc. sulphuric acid using a water separator. After 3 h another 3.56 ml methylvinylketone were added and the mixture was boiled for a further 3 h. After cooling the reaction mixture was taken up in ethyl acetate, washed with water, dried and concentrated by rotary evaporation.

Provenance & Evidence