Acetone → HCID 9990218, compound

Participants

Reaction Conditions

Reaction Steps

In a typical reaction 1,2-dimethylenecyclohexane (0.239 g, 2.21 mmol) was added via a disposable syringe to the highly reactive magnesium (3.53 mmol) in THF (20 mL). After being stiffed at room temperature for 4 hours, the reaction mixture was allowed to stand until the solution became transparent (approximately 2 hours). The yellowish gold THF solution of the complex was then separated from the excess magnesium by cannulating the solution to another flask under argon. The THF solution of newly formed magnesium complex of 1,2-dimethylenecyclohexane was cooled to -78° C. using a dry ice/acetone bath, and acetone (0.122 g, 2.10 mmol) was added via a disposable syringe. The mixture was stirred at -78° C. for 10 minutes, then gradually warmed to 0° C. Carbon dioxide was then bubbled through the reaction mixture for 10 minutes at 0° C., and another 10 minutes at room temperature. An aqueous solution of 1.5 N HCl (10 mL) was added at 0° C. The reaction mixture was slightly heated at 40° C. for 1 hour. After cooling to room temperature, the mixture was extracted with diethyl ether (3×20 mL). The combined organic phases were washed with saturated aqueous NaHCO3 (2×20 mL) and brine (20 mL) and dried over anhydrous MgSO4. Removal of solvents and flash column chromatography gave 4,4-dimethyl-6-methylene-3-oxaspiro[4.5]decan-2-one (0.279 g) in 68% yield. The following scheme illustrates this route for spiro γ-lactone synthesis. ##STR35##

Provenance & Evidence