Acetaldehyde → 3-Hydroxy-1-(2,6,6-trimethylcyclohexa-1,3-dien-1-yl)butan-1-one

Participants

Reaction Conditions

Reaction Steps

Into a 2-liter reaction flask equipped with a mechanical stirrer, cooling bath, 250 ml, addition funnel, nitrogen purge, water-cooled condenser, gas bubbler and thermometer, is placed 427 ml (1.3 moles) of a 3-molar solution of methyl magnesium chloride in tetrahydrofuran. 200 Grams (1.22 moles) of 2,6,6-trimethyl-1-acetylcyclohexa-1,3-diene are added dropwise from the addition funnel at a rate sufficient to produce methane. Cooling is applied as necessary to maintain the reaction temperature between 30 and 35° C. Following completion of the addition of the 2,6,6-trimethyl-1-acetylcyclohexa-1,3-diene, the reaction mass is stirred until no further methane is evolved. The reaction mass is then cooled to a temperature in the range of from 0° C. to 5° C., and 59 grams of acetaldehyde is added dropwise with stirring while maintaining the reaction mass temperature at about 10° C. The reaction is slightly exothermic. 15 Minutes after the completion of the addition of acetaldehyde, acetic acid is added dropwise while maintaining the temperature of the reaction mass at about 10° C. Following the addition of acetic acid, the reaction mass is permitted to reach room temperature. The reaction mass is then washed into a separatory funnel with water to dissolve the salt therein. The resulting organic layer is washed with saturated sodium chloride, saturated sodium bicarbonate, and then saturated sodium chloride. The washed organic layer is then dried over anhydrous magnesium sulfate and concentrated on a rotovap yielding 256 grams of residue.

Provenance & Evidence