Racemization enolizable hydrogens CH, CH H+or-OH a carbons (R)configuration enol (achiral) (S)configuration Copyright2010 Pearson Prentice Hall,Inc. For aldehydes and ketones,the keto form is greatly favored at equilibrium. ■ If a chiral carbon has an enolizable hydrogen atom,a trace of acid or base allows that carbon to invert its configuration,with the enol serving as the intermediate.This is called racemization. Chapter 22 8 Chapter 22 8 Racemization ▪ For aldehydes and ketones, the keto form is greatly favored at equilibrium. ▪ If a chiral carbon has an enolizable hydrogen atom, a trace of acid or base allows that carbon to invert its configuration, with the enol serving as the intermediate. This is called racemization