Chapter 7, Problem 7.26P

Interpretation Introduction

(a)

Interpretation:

Curved arrow and the product formed for the given nucleophilic addition step are to be drawn.

Concept introduction:

The curved arrow drawn from the nucleophile (electron rich species) to the polar pi-bond (electron poor species) represents the flow of electrons from an electron rich site to an electron poor site. The second curved arrow is drawn from the center of double or triple bond to the electronegative atom. A new bond is formed between the nucleophile and the electron deficient atom.

Answer to Problem 7.26P

The curved arrow and the product formed in the given nucleophilic addition step is drawn as:

Explanation of Solution

In the given nucleophilic addition step is:

In this step, ${\text{CH}}_{\text{3}}\text{OK}$ is treated as ${\text{CH}}_{\text{3}}{\text{O}}^{\text{-}}$ which acts as a nucleophile (electron rich site) whereas carbonyl carbon acts as an electrophile (electron poor site). Thus, the first curved arrow is drawn from ${\text{CH}}_{\text{3}}{\text{O}}^{\text{-}}$ to the electron poor C atom of $\text{C = O}$, and the second curved arrow is drawn from the middle of $\text{C = O}$ bond to O atom.

Thus, the curved arrows for the given nucleophilic addition step are drawn as:

The new bond in the product is formed between the electron rich O atom from the nucleophile and the electron poor C atom of the carbonyl group.

Conclusion

The curved arrow represents the flow of electrons from an electron rich site to an electron poor site.

Interpretation Introduction

(b)

Interpretation:

Curved arrow and the product formed for the given nucleophilic addition step are to be drawn.

Concept introduction:

The curved arrow drawn from the nucleophile (electron rich species) to the polar pi-bond (electron poor species) represents the flow of electrons from an electron rich site to an electron poor site. The second curved arrow is drawn from the center of double or triple bond to the electronegative atom. A new bond is formed between the nucleophile and the electron deficient atom.

Answer to Problem 7.26P

The curved arrow and the product formed in the given nucleophilic addition step is drawn as:

Explanation of Solution

In the given nucleophilic addition step is:

In this step ${\text{CH}}_{\text{3}}\text{Li}$ is treated as ${\text{CH}}_{\text{3}}^{\text{-}}$ which acts as a nucleophile (electron rich site) whereas carbonyl carbon acts as an electrophile (electron poor site). Thus, the first curved arrow is drawn from ${\text{CH}}_{\text{3}}^{\text{-}}$ to the electron poor C atom of $\text{C = O}$, and the second curved arrow is drawn from the middle of $\text{C = O}$ bond to O atom.

Thus, the curved arrows for the given nucleophilic addition step are drawn as:

The new bond in the product is formed between electron rich C atom from the nucleophile and electron poor C atom of the carbonyl group.

Conclusion

The curved arrow represents the flow of electrons from electron rich site to electron poor site.

Interpretation Introduction

(c)

Interpretation:

Curved arrow and the product formed for the given nucleophilic addition step are to be drawn.

Concept introduction:

The curved arrow drawn from the nucleophile (electron rich species) to the polar pi-bond (electron poor species) represents the flow of electron from an electron rich site to an electron poor site. The second curved arrow is drawn from the center of double or triple bond to the electronegative atom. A new bond is formed between the nucleophile and the electron deficient atom.

Answer to Problem 7.26P

The curved arrow and the product formed in the given nucleophilic addition step is drawn as:

Explanation of Solution

In the given nucleophilic addition step is:

In this step ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{MgBr}$ is treated as ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}^{\text{-}}$ which acts as nucleophile (electron rich site) whereas carbon atom of $\text{C}\equiv \text{N}$ acts as an electrophile (electron poor site). Thus, the first curved arrow is drawn from ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}^{\text{-}}$ to the electron poor C atom of $\text{C}\equiv \text{N}$, and the second curved arrow is drawn from the middle of $\text{C}\equiv \text{N}$ bond to N atom.

Thus, the curved arrows for the given nucleophilic addition step are drawn as:

The new bond in the product is formed between electron rich C atom from the nucleophile and electron poor C atom.

Conclusion

Curved arrow represents the flow of electrons from electron rich site to electron poor site.

Interpretation Introduction

(d)

Interpretation:

Curved arrow and the product formed for given nucleophilic addition step are to be drawn.

Concept introduction:

The curved arrow drawn from the nucleophile (electron rich species) to the polar pi-bond (electron poor species) represents the flow of electron from an electron rich site to an electron poor site. The second curved arrow is drawn from the centre of double or triple bond to the electronegative atom. A new bond is formed between the nucleophile and the electron deficient atom.

Answer to Problem 7.26P

The curved arrow and the product formed in the given nucleophilic addition step is drawn as:

Explanation of Solution

In the given nucleophilic addition step is:

In this step ${\text{NaBH}}_{\text{4}}$ is treated as ${\text{H}}^{\text{-}}$ acts as a nucleophile (electron rich site) whereas carbonyl carbon acts as an electrophile (electron poor site). Thus, the first curved arrow is drawn from ${\text{H}}^{\text{-}}$ to the electron poor C atom of $\text{C = O}$, and the second curved arrow is drawn from the middle of $\text{C = O}$ bond to O atom.

Thus, the curved arrows for the given nucleophilic addition step are drawn as:

The new bond in the product is formed between the electron rich H atom from the nucleophile and the electron poor C atom of the carbonyl group.

Conclusion

Curved arrow represents flow of electrons from electron rich site to electron poor site.

Interpretation Introduction

(e)

Interpretation:

Curved arrow and the product formed for given nucleophilic addition step are to be drawn.

Concept introduction:

The curved arrow drawn from the nucleophile (electron rich species) to the polar pi-bond (electron poor species) represents the flow of electron from an electron rich site to an electron poor site. The second curved arrow is drawn from the center of double or triple bond to the electronegative atom. A new bond is formed between the nucleophile and the electron deficient atom.

Answer to Problem 7.26P

The curved arrow and the product formed in the given nucleophilic addition step is drawn as:

Explanation of Solution

In the given nucleophilic addition step is:

In this step $\text{NaOH}$ is treated as ${\text{HO}}^{\text{-}}$ which acts as nucleophile (electron rich site) whereas carbonyl carbon acts as an electrophile (electron poor site). Thus, the first curved arrow is drawn from ${\text{HO}}^{\text{-}}$ to the electron poor C atom of $\text{C = O}$, and the second curved arrow is drawn from the middle of $\text{C = O}$ bond to O atom.

Thus, the curved arrows for the given nucleophilic addition step are drawn as:

The new bond in the product is formed between electron rich O atom from the nucleophile and electron poor C atom of the carbonyl group.

Conclusion

Curved arrow represents the flow of electrons from electron rich site to electron poor site.

Interpretation Introduction

(f)

Interpretation:

Curved arrow and the product formed for the given nucleophilic addition step are to be drawn.

Concept introduction:

The curved arrow drawn from the nucleophile (electron rich species) to the polar pi-bond (electron poor species) represents the flow of electron from an electron rich site to an electron poor site. The second curved arrow is drawn from the center of double or triple bond to the electronegative atom. A new bond is formed between the nucleophile and the electron deficient atom.

Answer to Problem 7.26P

The curved arrow and the product formed in the given nucleophilic addition step is drawn as:

Explanation of Solution

In the given nucleophilic addition step is:

In the above step, ${\text{COCH}}_{\text{3}}^{\text{-}}$ which acts as a nucleophile (electron rich site) whereas carbonyl carbon acts as an electrophile (electron poor site). Thus, the first curved arrow is drawn from ${\text{CH}}_{\text{3}}{\text{O}}^{\text{-}}$ to the electron poor C atom of $\text{C = O}$, and the second curved arrow is drawn from the middle of $\text{C = O}$ bond to O atom.

Thus, the curved arrows for the given nucleophilic addition step are drawn as:

The new bond in the product is formed between the electron rich C atom from the nucleophile and the electron poor C atom of the carbonyl group.

Conclusion

Curved arrow represents the flow of electrons from electron rich site to electron poor site.