Iodine → 6,6-dimethylhept-1-en-4-yn-3-ol

Participants

Reaction Steps

At dry and inert atmosphere, magnesium (6.4 gr., 0.26 mole) was heated with a trace of iodine until brown vapors evolved (−60° C). It was cooled down to room temperature and toluene (300 ml) and tetrahydrofuran (30 ml) were added. The mixture was heated to 450-50° C. and a mixture of ethyl bromide (30 gr., 0.26 mole) and toluene (30 ml) was added dropwise. The mixture was stirred at 50° C. until all the magnesium had practically been consumed. The mixture was cooled and a mixture of t-butylacetylene (20 gr., 0.24 mole) mixed with toluene (20 ml) was added gradually. The mixture was stirred at 30°-40° C. for 4-6 hours. Progress of the reaction could be monitored by the evolution of ethane. The reaction mixture was cooled to 0° C.-5° C. and a mixture of acrolein (stabilized by hydroquinone) (14 gr., 0.25 mole) diluted with toluene (20 ml) was added gradually during 1 hour. The mixture was heated to room temperature and stirred for 4 hours. The reaction mixture was quenched with ammonium chloride solution. The phases were separated. The organic phase was extracted with toluene (3×50 ml). The combined organic phases were washed with water to neutrality. The solution was dried and the solvent stripped. The crude product was obtained (20.2 gr., 65% yield). The crude product was distilled (boiling point 68° C.-69.5° C. at 12 mbar) to give pure 6,6-dimethylhept-1-en-4-yn-3-ol (16.1 gr., 48%).

Provenance & Evidence