Which is the unsaturated carbonyl compound formed by the dehydration of the following b-hydroxy carbonyl compound?
A)I
B)II
C)I and II
D)None of the choices

Question

Which is the unsaturated carbonyl compound formed by the dehydration of the following b-hydroxy carbonyl compound? 
A)I 
B)II 
C)I and II 
D)None of the choices

Quizplus · Accepted Answer

The b-hydroxy carbonyl compound shown in the image is an aldol. When aldols undergo dehydration they form unsaturated carbonyl compounds. The dehydration reaction involves removal of a molecule of water (H2O) from the alpha-carbon and the beta-carbon.

In this case, the molecule of water would be removed from the hydroxyl group (-OH) attached to the beta-carbon and the hydrogen attached to the alpha-carbon. This would result in the formation of a double bond between the alpha-carbon and the beta-carbon, and the carbonyl group would be retained.

Option I shows the product formed by removing a molecule of water from the given aldol. However, this product is a saturated ketone, not an unsaturated carbonyl compound.

Option II shows the correct unsaturated carbonyl compound formed by removing a molecule of water from the given aldol. Therefore, the correct answer is B.

Which Is the Unsaturated Carbonyl Compound Formed by the Dehydration