Chapter 21, Problem 21.46P

Draw the products of each reaction.

a. e.

b. f.

c. g.

d. h.

Interpretation Introduction

(a)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: A carbonyl compound (aldehyde or ketone) reacts with $1^{\text{ο}}$ amine to yield imine, and reacts with $2^{\text{ο}}$ amine to yield enamine. The mechanism of both reactions are identical except for the last step. The last step for enamine formation involves loss of a proton from the adjacent $\text{C}-\text{H}$ bond, whereas the last step for imine formation involves loss of a proton from the $\text{N}$ atom itself.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 1.

Explanation of Solution

The given reaction involves the treatment of an aldehyde with a $1^{\text{ο}}$ amine.

A carbonyl compound (aldehyde or ketone) reacts with $1^{\text{ο}}$ amine to yield imine, and reacts with $2^{\text{ο}}$ amine to yield enamine. The mechanism of both reactions are identical except for the last step. The last step for enamine formation involves loss of a proton from the adjacent $\text{C}-\text{H}$ bond, whereas the last step for imine formation involves loss of a proton from the $\text{N}$ atom itself.

Thus, the product of the given reaction is,

Figure 1

Interpretation Introduction

(b)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: Acetals are the groups in which carbon atom is bonded with two $\text{OR}$ groups through single bonds. A carbonyl compound (aldehyde or ketone) yields an acetal, when it is treated with two equivalents of an alcohol or one equivalent of diol in the presence of strong acid.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 2.

Explanation of Solution

The given reaction involves the treatment of a ketone with a diol.

Acetals are the groups in which carbon atom is bonded with two $\text{OR}$ groups through single bonds. A carbonyl compound (aldehyde or ketone) yields an acetal, when it is treated with two equivalents of an alcohol or one equivalent of diol in the presence of strong acid.

Thus, the product of the given reaction is,

Figure 2

Interpretation Introduction

(c)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: The hydrolysis of both enamines and imines yield aldehydes or ketones. The mechanisms of both reactions are exactly opposite to their formations, as they are formed from the treatment of aldehyde/ketones with amines.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 3.

Explanation of Solution

The given reaction involves the hydrolysis of an imine.

The hydrolysis of both enamines and imines yield aldehydes orketones along with primary (imine) or secondary amine (enamine). The mechanisms of both reactions are exactly opposite to their formations, as they are formed from the treatment of aldehyde/ketones with amines.

Thus, the product of the given reaction is,

Figure 3

Interpretation Introduction

(d)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: A carbonyl compound (aldehyde or ketone) reacts with $1^{\text{ο}}$ amine to yield imine, and reacts with $2^{\text{ο}}$ amine to yield enamine. The mechanism of both reactions are identical except for the last step. The last step for enamine formation involves loss of a proton from the adjacent $\text{C}-\text{H}$ bond, whereas the last step for imine formation involves loss of a proton from the $\text{N}$ atom itself.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 4.

Explanation of Solution

The given reaction involves the treatment of ketone with $2^{\text{ο}}$ amine.

A carbonyl compound (aldehyde or ketone) reacts with $1^{\text{ο}}$ amine to yield imine, and reacts with $2^{\text{ο}}$ amine to yield enamine. The mechanism of both reactions are identical except for the last step. The last step for enamine formation involves loss of a proton from the adjacent $\text{C}-\text{H}$ bond, whereas the last step for imine formation involves loss of a proton from the $\text{N}$ atom itself.

Thus, the product of the given reaction is,

Figure 4

Interpretation Introduction

(e)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: Cyanohydrins are the nucleophilic addition product of carbonyl compounds in which ${}^{-}\text{CN}$ acts as a nucleophile. An acid catalyzed reaction of cyanohydrin leads to the formation of corresponding acid.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 5.

Explanation of Solution

The given reaction involves the hydrolysis of cyanohydrin compound.

Cyanohydrins are the nucleophilic addition product of carbonyl compounds in which ${}^{-}\text{CN}$ acts as a nucleophile. An acid catalyzed reaction of cyanohydrin leads to the formation of corresponding acid.

Thus, the product of the given reaction is,

Figure 5

Interpretation Introduction

(f)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: Hemiacetals are the groups in which carbon atom is bonded to one $\text{OR}$ group and one $\text{OH}$ group. Cyclic hemiacetals yield acetals, when they are treated with ethanol and an acid.

Answer to Problem 21.46P

The product of given reaction isdrawn in Figure 6.

Explanation of Solution

The given reaction involves the treatment of cyclic hemiacetal with ethanol in the presence of acid.

Hemiacetals are the groups in which carbon atom is bonded to one $\text{OR}$ group and one $\text{OH}$ group. Cyclic hemiacetals yield acetals, when they are treated with ethanol and an acid.

Thus, the product of the given reaction is,

<

Figure 6

Interpretation Introduction

(g)

Interpretation: The product of the given reaction is to be drawn.

Concept introduction: The hydrolysis of both enamines and imines yield aldehydes or ketones along with primary (imine) or secondary amine (enamine). The mechanisms of both reactions are exactly opposite to their formations, as they are formed from the treatment of aldehyde/ketones with amines.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 7.

Explanation of Solution

The given reaction involves the hydrolysis of an enamine.

The hydrolysis of both enamines and imines yield aldehydes or ketones along with primary (imine) or secondary amine (enamine). The mechanisms of both reactions are exactly opposite to their formations, as they are formed from the treatment of aldehyde/ketones with amines.

Thus, the Product of the given reaction is,

Figure 7

Interpretation Introduction

(h)

Interpretation: The product of given reaction is to be drawn.

Concept introduction: The Wittig reaction utilizes carbon nucleophile from the Wittig reagent to yield alkenes. When a carbonyl compound is treated with a Wittig reagent, the $\text{C}=\text{O}$ bond of carbonyl is replaced by $\text{C}=\text{C}$, with by-product triphenylphosphine oxide $\left({\text{Ph}}_{\text{3}}\text{P}=\text{O}\right)$.

Answer to Problem 21.46P

The product of the given reaction isdrawn in Figure 8.

Explanation of Solution

The given reaction involves the hydrolysis of an enamine.

The Wittig reaction utilizes carbon nucleophile from the Wittig reagent to yield alkenes. When a carbonyl compound is treated with a Wittig reagent, the $\text{C}=\text{O}$ bond of carbonyl is replaced by $\text{C}=\text{C}$, with by-product triphenylphosphine oxide $\left({\text{Ph}}_{\text{3}}\text{P}=\text{O}\right)$.

Thus, the product of the given reaction is,

Figure 8

Conclusion

(a) The product of the given reaction is drawn in Figure 1.

(b) The product of the given reaction is drawn in Figure 2.

(c) The product of the given reaction is drawn in Figure 3.

(d) The product of the given reaction is drawn in Figure 4.

(e) The product of the given reaction is drawn in Figure 5.

(f) The product of the given reaction is drawn in Figure 6.

(g) The product of the given reaction is drawn in Figure 7.

(h) The product of the given reaction is drawn in Figure 8.