question_answer

Which of the following compounds will most readily be dehydrated to give alkene under acidic condition? [JEE Main 16-4-2018]

A)  2-Hydroxycyclopentanone

B)  1-Pentanol

C)  3-Hydroxypentan-2-one

D)  4-Hydroxypentan-2-one

Correct Answer: C , D

Solution :

3-Hydroxypentan-2-one and 4-Hydroxypentan-2-one will most readily be dehydrated to give alkene under acidic condition. This will lead to formation of \[\alpha -\beta \]unsaturated ketone. Note: Dehydration of 2-Hydroxycyclopentanone will lead to C = C double bond in 5 member ring that will cause strain and product is less likely to be formed.

Solution :

3-Hydroxypentan-2-one and 4-Hydroxypentan-2-one will most readily be dehydrated to give alkene under acidic condition. This will lead to formation of \[\alpha -\beta \]unsaturated ketone. Note: Dehydration of 2-Hydroxycyclopentanone will lead to C = C double bond in 5 member ring that will cause strain and product is less likely to be formed.