Synthesis of [6]-gingerol

[6]-Gingerol is the main pungent component of fresh ginger. It can be prepared by directed aldol addition from zingerone, a methyl ketone also found in ginger.

With slightly more than two equivalents of LDA at −78 °C, first the phenol and then the methyl group of the ketone (the kinetic, less substituted enolate) are deprotonated. The enolate reacts with hexanal to form the β-hydroxy ketone without self-condensation of the ketone. The racemate is obtained; the natural product is the (S) enantiomer.