3-Methyl-1-trichloromethyl-2-butenyl diazoacetate → 4-Trichloromethyl-6,6-dimethyl-2-oxo-3-oxabicyclo[3.1.0]hexane

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Reaction Steps

To a refluxing solution of cupric acetylacetonate (0.07 g, 0.27 mole) in 70 ml of dioxane was added drop-dropwise over a 31/2 hour period, under an argon atmosphere, a solution of (±)-3-methyl-1-trichloromethyl-2-butenyl diazoacetate (1.09 g, 0.004 moles) and cupric acetylacetonate (0.007 g, 0.027 mmole) in 10 ml of dioxane. The reaction mixture was then heated under reflux for one hour and evaporated to dryness, yielding a residue which was dissolved in ether. The ethereal solution was washed successively with two portions of aqueous 1 N hydrochloric acid, two portions of aqueous sodium bicarbonate, and twice with saturated aqueous sodium chloride. After drying the solution over magnesium sulfate, the ether was evaporated to afford a pale yellow oil, which was purified by column chromatography on a silica gel column using a 9/1 mixture of n-hexane/ethyl acetate as the eluant, to give (±)-4-trichloromethyl-6,6-dimethyl-2-oxo-3-oxabicyclo[3.1.0]hexane (0.55 g, 53% yield).

Provenance & Evidence