Dimethyl Sulfoxide → 1,1-Dimethyl-4-methylidenecyclohexane

Methyltriphenylphosphonium bromide (2.97 g, 8.3 mmol) was added in the dehydrated DMSO (8 mL) solution of sodium hydride (0.35 g, 8.7 mmol) in an ice bath. The reaction mixture was stirred at room temperature for 10 minutes, and the dehydrated DMSO solution (1.5 mL) of 4,4-dimethyl-cyclohexanone (1.0 g, 7.9 mmol) was added slowly in an ice bath. The reaction mixture was stirred at room temperature for 18 hours and poured into ice water. The organic layer was extracted with diethyl ether, and then the layer was washed with water and dried with anhydrous magnesium sulfate, and removed by filtration. The filtrate was concentrated until becoming about half in volume. The formed insoluble matter was removed by filtration, then the filtrate was removed by distillation under reduced pressure, and colorless oily matter (0.91 g) was obtained.