The compound that undergoes decarboxylation most readily under mild condition is :
-Keto acids undergoes decarboxylation most readly.
Decarboxylation is a chemical reaction where a carboxylic acid loses a carbon dioxide molecule to form a hydrocarbon or a substituted hydrocarbon. The ease of decarboxylation depends on the stability of the intermediate formed and the nature of the carboxylic acid.
Beta-keto acids and malonic acids undergo decarboxylation readily under mild conditions because they form a stable six-membered cyclic transition state or a resonance-stabilized enol intermediate. The decarboxylation mechanism involves:
Step 1: Intramolecular hydrogen bonding or proton transfer facilitates the reaction.
Step 2: Formation of a cyclic transition state (for beta-keto acids) or enol intermediate.
Step 3: Release of CO and formation of the final product.
Among the given options, the compound that is a beta-keto acid will decarboxylate most readily. Without the exact structures, based on typical examples:
- Option 1: Likely a simple carboxylic acid (less readily decarboxylates).
- Option 2: Could be a malonic acid derivative (decarboxylates readily).
- Option 3: Might be a beta-keto acid (decarboxylates most readily).
- Option 4: Possibly an alpha-keto acid (requires harsh conditions).
The beta-keto acid (option 3, if it is one) undergoes decarboxylation most readily due to the stabilization of the enol intermediate and low energy transition state.
Decarboxylation Reaction: General reaction for beta-keto acid:
Stability Factors: Resonance stabilization and cyclic transition state lower the activation energy.
Key Compounds: Acetoacetic acid (beta-keto acid) and malonic acid decarboxylate easily.
In the scheme given below, the total number of intramolecular aldol condensation products formed from ‘Y’ is
The major product of the following reaction is :
Match the reactions in column I with appropriate types of steps / reactive intermediate involved in these reactions as given in column II
| Column-I | Column-II |
 |
(p) Nucleophilic substitution |
 |
(q) Electrophilic substitution |
 |
(r) Dehydration |
 |
(s) Nucleophilic addition |
| (t) Carbanion |
The number of aldol reaction (s) that occurs in the given transformation is
