Q.13. - Organic Chemistry

Question

Question: Draw a stepwise mechanism for the conversion of heptane-2,6-dione to 3-methylcyclohex-2-enone with NaOEt, EtOH.

Step-by-Step Solution

Answer

Answer

Step 1: Aldol reaction

Aldol reaction in the presence of base is termed as base-catalyzed aldol reaction. It is performed under NaOEt, EtOH and is a reversible reaction.

Step 2: Explanation for the mechanism

In the first step of the reaction, $Et{O}^{-}$ from NaOEt abstracts an alpha hydrogen to create a nucleophilic carbon center. Then, the intermolecular attack takes place to form a six-membered ring.

 

Negative charge on oxygen abstracts proton from EtOH to form hydroxyl group in the compound. Further, $Et{O}^{-}$ abstracts proton to create negative charge. The rearrangement takes place to form 3-methylcyclohex-2-enone.

 

The mechanism is shown below:

Mechanism of the reaction