Question

Treatment of (HOCH₂CH₂CH₂CH₂)₂CO with acid forms a product of molecular formula C₉H₁₆O₂and a molecule of water. Draw the structure of the product and explain howit is formed.

Short answer

In an acetal, the carbonyl carbon is singly connected to two alkoxy groups. Hemiacetals are generated by combining a carbonyl compound with one alcohol equivalent.

Step-by-step solution

Formation of acetal and hemiacetal

In an acetal, the carbonyl carbon is singly connected to two alkoxy groups. Hemiacetals are generated by combining a carbonyl compound with one alcohol equivalent.

Pinacol-pinacolone rearrangement 

The transformation of 1,2-diol into a carbonyl compound happens using the pinacol-pinacolone rearrangement. An acid catalyst is necessary for this reaction to take place.

Treatment of  (HOCH2CH2CH2CH2)2CO with acid

The OH group on the right attacks the carbonyl carbon leading to the formation of the hemiacetal. The hemiacetal gets subjected to pinacol-pinacolone rearrangement to form the acetal that can be given as:

Treatment of(HOCH₂CH₂CH₂CH₂)₂CO with acid