70E - Organic Chemistry (Mcmurry)

Question

Carboxylic acids having a second carbonyl group two atoms away lose CO₂ (decarboxylate) through an intermediate enolate ion when treated with base. Write the mechanism of this decarboxylation reaction using curved arrows to show the electron flow in each step.

Step-by-Step Solution

Answer

The mechanism for the decarboxylation reaction using curved arrows for electron flow show can be found.

Step 1: Finding acetone as a product

The removal of the base a proton from the acid to give carboxylate anion. The electron shift from negatively charged oxygen using carbon chain undergoes carbonyl carbon which results in the CO₂ elimination and enolate anion formation. The picking up of enolate anion and tautomerizing of the product acetone yield. 

Step 2: Steps for the mechanism of decarboxylation reaction

The mechanism for the decarboxylation reaction using curved arrows to show the flow of electrons can be written as,