Sodium Methoxide → Spiro[2.5]octane-5,7-dione

Participants

Reaction Steps

23.3 g of crude [1-(2-oxo-propyl)-cyclopropyl]-acetic acid methyl ester (60% purity, from step 5) are dissolved in 135 ml of tetrahydrofuran and 17.1 g of a sodium methanolate solution in methanol (30% in methanol) are added at room temperature and the mixture is stirred for six hours. Then the solution is diluted with 135 ml of methyl tert-butyl ether and quenched with 135 ml of water. Stirring is continued for five minutes, then the phases are separated. The aqueous phase is extracted with 67.5 ml of methyl tert-butyl ether, then acidified to pH 2-3 with 37% HCl and washed twice with 67.5 ml of methyl tert-butyl ether each. The combined organic phases are washed with 18 ml of water and concentrated to dryness. The crude product is stirred with 18 ml of cold methyl tert-butyl ether and then the precipitate is isolated by filtration. The filter cake is washed with 18 ml of cold methyl tert-butyl ether to yield the product as an off-white solid.

Provenance & Evidence