Chapter 10, Problem 10.41P

Interpretation Introduction

(a)

Interpretation:

The product with the detailed mechanism for the given reaction is to be drawn.

Concept introduction:

The aldehyde or ketone can also be halogenated like alkylation by deprotonation of $\text{α}$ carbon followed by a nucleophilic substitution reaction with the halogen molecule. In the basic condition, multiple halogenation at $\text{α}$ carbon of aldehyde or ketones can be possible. In the first halogenation, the substitution of halogen takes place at $\text{α}$ carbon of ketone by the formation of enolate anion due to deprotonation. The $\text{α}$ carbon of ketone becomes more acidic after the first halogenation and can form a second enolate anion. The second enolate is more stable compared to the first one and undergoes further halogenation. This is due to the electron withdrawing effect of electronegative halogen atom, which stabilizes the negative charge on $\text{α}$ carbon.

Interpretation Introduction

(b)

Interpretation:

The product with detailed mechanism for the given reaction is to be drawn.

Concept introduction:

The aldehyde or ketone can also be halogenated like alkylation by deprotonation of $\text{α}$ carbon followed by a nucleophilic substitution reaction with the halogen molecule. In acidic condition, the reaction stops at a single halogenation step and no multiple halogenation occurs. The reaction proceeds via the formation of enol by protonation of carbonyl oxygen.