Chapter 22, Problem 22.25P

Interpretation Introduction

(a)

Interpretation:

The curve arrow mechanism which includes the formation of enamine X is to be stated.

Concept introduction:

The nucleophilic substitution reactions are the reactions in which one nucleophile attacks the electrophilic centre and eliminates another group in the compound. These reactions depend upon the nucleophilicity and concentration of the nucleophile.

The ${\text{S}}_{\text{N}}\text{2}$ reaction is a nucleophilic substitution bimolecular single step reaction in which the addition of nucleophile and removal of leaving group takes place simultaneously.

The ${\text{S}}_{\text{N}}1$ reaction is a nucleophilic substitution reaction in which the substitution of nucleophile takes place. This reaction takes place in two steps. There is generation of carbocation in the first step and in the second step the nucleophile attacks at the carbocation for the corresponding product.

Interpretation Introduction

(b)

Interpretation:

The curve arrow mechanism for the conversion of enamine X to the given product is to be stated.

Concept introduction:

In Aldol condensation reaction, the base abstracts an acidic proton from the carbon atom to form enolate. This enolate or enol reacts with carbonyl compound that leads to the formation of $\text{β}-$ hydroxyaldehyde or $\text{β}-$ hydroxyketone which on further dehydration gives the conjugated enone.

The Aldol condensation reaction that takes place within the molecule in presence of strong base is known as intramolecular aldol reactions. This reaction takes place within the dicarbonyl compounds in which one carbonyl group forms the enolate that acts as a nucleophile and reacts with second carbonyl group which acts as electrophile.

Interpretation Introduction

(c)

Interpretation:

The hydrolysis mechanism for the reaction that gives the ketone and generates the catalyst is to be stated.

Concept introduction:

The chemical process in which the water molecule is added is known as hydrolysis. The process of hydrolysis prefers acidic condition. The addition of water molecule results in the cleavage of two or more bonds. The water molecule acts as a nucleophile in various reactions such as substitution, elimination and fragmentation reaction.

The products of hydrolysis of imines are carbonyls and amines.