Diethyl Ether → Mesityl oxide

Participants

Reaction Steps

Sodium (30 g.) was dissolved in liquid ammonia (1,500 ml.) and acetylene was passed through the solution until the blue color was discharged. Magnesium turnings (10 g.) were added and the mixture was stirred for 18 hours while acetylene was passed slowly through it. During this period, almost all the magnesium dissolved. A solution of mesityloxide (10.7 g.) in diethyl ether (300 ml.) was cooled to -20° to -40°C. and was added to the reaction mixture over a period of about 5 minutes. The mixture was stirred for 5 hours, the ammonia was evaporated until the temperature of the residue reached -20°C., and the residue was dropped into a solution of sulfuric acid (200 ml.) in water (1,200 ml.) which was maintained at -5° to +15°C. The etheral layer was separated and the aqueous phase was extracted with two portions of diethyl ether (100 ml. each). The combined etheral extracts were washed with a mixture of aqueous saturated sodium bicarbonate solution (20 ml.) and saturated brine (80 ml.), then dried over sodium sulfate and the ether removed by distillation at atmospheric pressure. Distillation of the residue at 25°-34°C./3 mmHg yielded 3,5-dimethylhex-4-en-1-yn-3-ol (57.3 g.) and mesityl oxide (30.0 g.). The conversion of mesityl oxide was thus 72.0% and the yield of product 58.8%.

Provenance & Evidence