Chapter 22, Problem 22.57AP

Interpretation Introduction

(a)

Interpretation:

The principal organic product expected when isobutyraldehyde reacts with the lithium enolate of acetone followed by ${\text{H}}_{\text{2}}\text{O}/{\text{H}}_{\text{3}}{\text{O}}^{+}$ is to be stated.

Concept introduction:

The nucleophilic addition reactions of carbonyl compounds are well known due to the polarity of the carbonyl group. The nucleophile attacks on the carbonyl and adds to the carbonyl carbon. The addition of enolate ion on the carbonyl compounds is known as aldol reaction.

Answer to Problem 22.57AP

The principal organic product obtained when isobutyraldehyde reacts with the lithium enolate of acetone followed by ${\text{H}}_{\text{2}}\text{O}/{\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Explanation of Solution

The principal organic product obtained when isobutyraldehyde reacts with the lithium enolate of acetone followed by ${\text{H}}_{\text{2}}\text{O}/{\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Figure 1

The enolate ions attack rapidly on the carbonyl group. The enolate ion attacks the carbonyl carbon from the carbon-side and undergoes addition on the carbonyl compound.

Lithium enolate of acetone attacks on the isobutyraldehyde from the carbon side and adds on the molecule. The acidic workup converts the oxide ion generated into alcohol group.

Conclusion

The principal organic product obtained when isobutyraldehyde reacts with the lithium enolate of acetone followed by ${\text{H}}_{\text{2}}\text{O}/{\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The principal organic product expected when isobutyraldehyde reacts with the lithium enolate of ethyl $\text{2-methylpropanoate}$ followed by dilute ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is to be stated.

Concept introduction:

The nucleophilic addition reactions of carbonyl compounds are well known due to the polarity of the carbonyl group. The nucleophile attacks on the carbonyl and adds to the carbonyl carbon. The addition of enolate ion on the carbonyl compounds is known as aldol reaction.

Answer to Problem 22.57AP

The principal organic product obtained when isobutyraldehyde reacts with the lithium enolate of ethyl $\text{2-methylpropanoate}$ followed by dilute ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Explanation of Solution

The principal organic product obtained when isobutyraldehyde reacts with the lithium enolate of ethyl $\text{2-methylpropanoate}$ followed by dilute ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Figure 2

The enolate ions attack rapidly on the carbonyl group. The enolate ion attacks the carbonyl carbon from the carbon-side and undergoes addition on the carbonyl compound.

Lithium enolate of $\text{2-methylpropanoate}$ attacks on the isobutyraldehyde from the carbon side and adds on the molecule. The acidic workup converts the oxide ion generated into alcohol group.

Conclusion

The principal organic product obtained when isobutyraldehyde reacts with the lithium enolate of ethyl $\text{2-methylpropanoate}$ followed by dilute ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation:

The principal organic product expected when isobutyraldehyde reacts with ethyl $\alpha \text{-bromoacetate}$ and $\text{Zn}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is to be stated.

Concept introduction:

The nucleophilic addition reactions of carbonyl compounds are well known due to the polarity of the carbonyl group. The nucleophile attacks on the carbonyl and adds to the carbonyl carbon. The addition of enolate ion on the carbonyl compounds is known as aldol reaction.

Answer to Problem 22.57AP

The principal organic product obtained when isobutyraldehyde reacts with ethyl $\alpha \text{-bromoacetate}$ and $\text{Zn}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Explanation of Solution

The principal organic product obtained when isobutyraldehyde reacts with ethyl $\alpha \text{-bromoacetate}$ and $\text{Zn}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Figure 3

The enolate ions attack rapidly on the carbonyl group. The enolate ion attacks the carbonyl carbon from the carbon-side and undergoes addition on the carbonyl compound.

The zinc metal converts the ethyl $\alpha \text{-bromoacetate}$ molecule into the enolate ion. The zinc metal takes up the bromine from the molecule.

The enolate ion generated attacks on the isobutyraldehyde from the carbon side and adds on the molecule. The acidic workup converts the oxide ion generated into alcohol group.

This reaction is a name reaction known as Reformatsky reaction.

Conclusion

The principal organic product obtained when isobutyraldehyde reacts with ethyl $\alpha \text{-bromoacetate}$ and $\text{Zn}$ then ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown in Figure 3.

Interpretation Introduction

(d)

Interpretation:

The principal organic product expected when isobutyraldehyde reacts with diethyl malonate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is to be stated.

Concept introduction:

The nucleophilic addition reactions of carbonyl compounds are well known due to the polarity of the carbonyl group. The nucleophile attacks on the carbonyl and adds to the carbonyl carbon. The addition of enolate ion on the carbonyl compounds is known as aldol reaction.

Answer to Problem 22.57AP

The principal organic product obtained when isobutyraldehyde reacts with diethyl malonate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is shown below.

Explanation of Solution

The principal organic product obtained when isobutyraldehyde reacts with diethyl malonate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is shown below.

Figure 4

The enolate ions attack rapidly on the carbonyl group. The enolate ion attacks the carbonyl carbon from the carbon-side and undergoes addition on the carbonyl compound.

Malonic ester is converted into the enolate ion by the secondary amine taken as the catalyst. The secondary amine pyridine taken here is basic in nature and takes up the acidic proton of the malonic ester.

The enolate ion generated attacks on the isobutyraldehyde from the carbon side and adds on the molecule. The acidic workup converts the oxide ion generated into alcohol group.

This reaction is a name reaction known as Knoevenagal reaction.

Conclusion

The principal organic product obtained when isobutyraldehyde reacts with diethyl malonate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is shown in Figure 4.

Interpretation Introduction

(e)

Interpretation:

The principal organic product expected when isobutyraldehyde reacts with ethyl acetoacetate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is to be stated.

Concept introduction:

The nucleophilic addition reactions of carbonyl compounds are well known due to the polarity of the carbonyl group. The nucleophile attacks on the carbonyl and adds to the carbonyl carbon. The addition of enolate ion on the carbonyl compounds is known as aldol reaction.

Answer to Problem 22.57AP

The principal organic product obtained when isobutyraldehyde reacts with ethyl acetoacetate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is shown below.

Explanation of Solution

The principal organic product obtained when isobutyraldehyde reacts with ethyl acetoacetate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is shown below.

Figure 5

The enolate ions attack rapidly on the carbonyl group. The enolate ion attacks the carbonyl carbon from the carbon-side and undergoes addition on the carbonyl compound.

Ethyl acetoacetate is converted into the enolate ion by the secondary amine taken as the catalyst. The secondary amine pyridine taken here is basic in nature and takes up the acidic proton of the malonic ester.

The enolate ion generated attacks on the isobutyraldehyde from the carbon side and adds on the molecule. The acidic workup converts the oxide ion generated into alcohol group.

This reaction is a name reaction known as Knoevenagal reaction.

Conclusion

The principal organic product obtained when isobutyraldehyde reacts with ethyl acetoacetate and a secondary amine $\left({\text{R}}_{\text{2}}\ddot{\text{N}}\text{H}\right)$ catalyst is shown in Figure 5.