Acetone → (1R*,5S*)-3,4-dichloro-5-methyl-8-oxabicyclo[3.2.1]octa-3,6-dien-2-one

Participants

Reaction Conditions

Reaction Steps

Silver nitrate (166 g, 0.982 mol) is added to a stirred mixture of (1R*,5S*)-2,3,4,4-tetrachloro-1-methyl-8-oxabicyclo[3.2.1]octa-2,6-diene (83 g, 0.491 mol), acetone (1500 ml) and water (1500 ml) and the mixture is heated at 65° C. for 16 hours. The reaction mixture is cooled to room temperature, and a saturated solution of aqueous sodium bicarbonate is added to adjust the pH to 7-8. The mixture is filtered through a plug of diatomaceous earth, and the filtrate is concentrated in vacuo to remove most of the acetone. The aqueous mixture is extracted with ethyl acetate (3×500 ml) and the organic extracts are combined, dried over anhydrous sodium sulfate, filtered and the filtrate is evaporated. The residue is purified by flash column chromatography on silica gel to give (1R*,5S*)-3,4-dichloro-5-methyl-8-oxabicyclo[3.2.1]octa-3,6-dien-2-one (29.5 g) as a yellow oil.

Provenance & Evidence