ACIDITY OF CARBOXYLIC-ACIDS - RESONANCE DELOCALIZATION OR INDUCTION

On the basis of calculated acidities of the vinylogues of formic acid and vinyl alcohol, Dewar and Krull have concluded that the higher acid ity of carboxylic acids relative to alcohols is due to stabilization o f the conjugate anion by resonance delocalization. More detailed calcu lations on some of the compounds that they have considered shows indee d that delocalization of charge in the anion plays a role in the acidi ty of buta-1,3-dien-1-ol 1 relative to vinyl alcohol and of 3-hydroxyp rop-2-enal 2 relative to formic acid. However, these calculations show that this conclusion is not applicable to the relative acidities of e thanol, vinyl alcohol and formic acid or of 2 relative to 1.These are due to the charge distribution in the neutral molecule, in keeping wit h the ideas proposed by Siggel et al.