Fundamentals of Organic ChemistryChemistryCarboxylic Acid Derivatives
Identify the correct order of the ease of decarboxylation for the following three carboxylic acids: (i) (ii) (iii)
Options
- A(iii) = (ii) > (i)
- B(iii) > (ii) = (i)
- C(iii) = (ii) = (i)
- D(iii) > (ii) > (i)
Correct answer
D. (iii) > (ii) > (i)
Step-by-step solution
To determine the ease of decarboxylation, we must first identify the type of each carboxylic acid given: (i) The structure is CH₂=CH-COOH , which is an , -unsaturated carboxylic acid. (ii) The structure is CH₃-CH=CH-CH₂-COOH , which is a , -unsaturated carboxylic acid. (iii) The structure is CH₃-CO-CH₂-COOH , which is a -keto carboxylic acid. Now, let us compare their mechanisms for decarboxylation upon heating: 1. -keto acids (iii) undergo decarboxylation very easily (even at mild temperatures like 50^ C ) via a s