Acetic Acid → (E)-6-acetoxy-2-(3-oxooct-1-enyl)bicyclo[3,3,0]octane

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Reaction Steps

A suspension of the sodium salt of dimethyl (2-oxoheptyl)phosphonate (0.105 g; prepared as described in Reference Example 55) in tetrahydrofuran (5.3 ml) at 0° C. was treated dropwise with a solution of 6-acetoxy-2-formylbicyclo[3,3,0]octane (70 mg; prepared as described in Reference Example 21 and predominantly in the 2β-configuration) in tetrahydrofuran (1.0 ml) with stirring. The resulting mixture was stirred for 18 hours at ambient temperature under an atmosphere of argon. The mixture was then treated dropwise with a solution of glacial acetic acid (200 mg) in diethyl ether (1 ml), and then the solution was concentrated in vacuo. The residue was treated with diethyl ether (20 ml) and water (20 ml) and the organic layer was separated. The aqueous layer was extracted with diethyl ether (3×20 ml). The combined extracts were washed with water and then with saturated aqueous sodium chloride solution, dried over magnesium sulphate and concentrated in vacuo, to give an oil which was subjected to chromatography on a silica gel column, to give (E)-6-acetoxy-2-(3-oxooct-1-enyl)bicyclo[3,3,0]octane (65.7 mg), predominantly in the 2β-configuration.

Provenance & Evidence