Acetaldehyde → cis-1-(2,2,6-Trimethylcyclohexyl)-3-butanol

Participants

Reaction Steps

To 750 ml of an etheral solution of ethylmagnesium bromide (prepared from 302 g (2.7 moles) of ethyl bromide and 58,7 g (2.4 moles) magnesium turnings in 550 ml of ether) is added with cooling and stirring a solution of 238 g (2.2 moles) of freshly distilled dry N-methylaniline in 700 ml of dry benzene (N2 atmosphere). To the above freshly prepared solution of N-methylanilinomagnesium bromide is added during 25-30 minutes a solution of 370 g (2.2 moles) of 1-acetyl-2,2,6-trimethyl cyclohexane (VI) in 370 ml of dry benzene while keeping the temperature at 15° C. After the addition of the ketone, the solution is allowed to stand for 30 minutes. A solution of 145.5 g (3.3 moles) of freshly distilled acetaldehyde in 150 ml of dry benzene is then added during 45 minutes, keeping the temperature at -13° to -10° C. After the addition of the aldehyde, the solution is allowed to stand for 90 minutes at the same temperature. 2000 ml of 3N hydrochloric acid is then added with stirring and cooling. The organic layer is separated and washed 6 times with 1000 ml 3N hydrochloric acid (to remove the N-methylaniline) and finally with 500 ml of water, 500 ml of sodium bicarbonate solution, and then water. The combined organic layers are dried over, anhydrous sodium sulfate and the solvents are removed by distillation at reduced pressure. The residue is distilled through a short Vigreux column. The product, cis-1-(2,2,6-trimethylcyclohexyl)-3-butanolone-1 (containing about 10% of the trans isomer) is collected at 98°-104° C/1 mm; yield 320 g (70%).

Provenance & Evidence