Question

Draw the structures of organic compounds A and B. Omit all of the byproducts. acetaldehyde H₂O

 

Answer 1

Concepts and reason

This problem is based on the concept of Grignard reagent reactivity. The grignard reagent is a very good nucleophile in the case of carbonyl compounds. It is made up of the reaction of haloalkane with Mg in the presence of ether. It attacks carbonyl compounds followed by the treatment with water and forms corresponding alcohol.

Fundamentals

In order to predict the reactant from the product, the reaction should be written backward (from product to reactant).

 

The reaction is given below:

The product contains five carbons of which two carbons came from acetaldehyde and three carbons came from a nucleophile that is propyl magnesium bromide.

 

The first reaction of synthesis is given below:

The structures of compounds \(A\) and \(B\) are as follow:

In this synthesis, propyl bromide molecule undergoes a chemical reaction with \(\mathrm{Mg}\) in the presence of ether in order to form Grignard reagent which on reaction with acetaldehyde followed by the treatment of water forms alcohol which pentan-2-ol.