Methanol → 2,6-Dimethyl-6-(3-methyl-but-2-enyl)-cyclo-hex-2-enone

Participants

Reaction Conditions

Reaction Steps

Sodium hydride (60%, 85 g, 2.13 mol) was added portionwise to a solution of 2,6-dimethylphenol (250 g, 2.05 mol) in 2 L of toluene at 10-15° C. The resulting suspension was stirred for 45 min. The mixture was cooled to 5° C., and prenyl chloride (262 g, 2.13 mol, 85%) was added during 1.5 h keeping the temperature at 5° C. The mixture was then stirred for further 2 h at 10-15° C. Methanol (1 L) and palladium (2.5 g, 10% on charcoal) was added and the gray suspension was hydrogenated at 0.3 bar overpressure, keeping the temperature at 20-22° C. (ice bath). The suspension was then filtered through a pad of celite. The yellow filtrate was washed with water (0.5 L), aqueous sodium hydroxide (0.5 L) and brine (0.5 L), dried (MgSO4) and concentrated in vacuo. The residue was distilled over a 5 cm Vigreux column to yield 318 g (81%, bp 78-82° C./0.05 Torr) of a colorless oil.

Provenance & Evidence