Chapter 10, Problem 10.59AP

Interpretation Introduction

(a)

Interpretation:

The given reaction is to be completed and explained to give the principal products.

Concept introduction:

The nucleophilic substitution reactions are the reactions in which nucleophile attacks the electrophilic centre and eliminates another group. 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 rate of reaction depends upon both the substrate and reactant in the rate law equation.

Answer to Problem 10.59AP

The complete reaction is shown below.

The tosyl chloride is used to make the hydroxide group a good leaving group by replacing its hydrogen with tosyl group. The $-\text{OTs}$ group thus formed is good leaving group and is replaced by the bromide nucleophile easily to give the benzyl chloride as the product.

Explanation of Solution

The given reaction is shown below.

Figure 1

The complete reaction with the products is shown below.

Figure 2

The reaction of the alcohols with tosyl chloride is the reaction to make the hydroxide group a good leaving group. The hydrogen is replaced by the tosyl group. The $-\text{OTs}$ is good leaving group which is substituted by bromide ion from to give the halide. The product thus obtained in the end is benzyl bromide.

Conclusion

The completed reaction is shown in Figure 2.

Interpretation Introduction

(b)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

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

The ${\text{S}}_{\text{N}}\text{2}$ reaction is a nucleophilic substitution bimolecular reaction in which the addition of nucleophile and elimination of a leaving group takes place simultaneously. The rate of reaction depends upon both the substrate and reactant in the rate law equation.

Answer to Problem 10.59AP

The complete reaction is shown below.

The acid is used to make the hydroxide group a good leaving group. The iodide group than substitutes the protonated hydroxide group to give halide product.

Explanation of Solution

The given reaction is shown below.

Figure 3

The complete reaction with the products is shown below.

Figure 4

The hydroxide group in alcohols is not a good leaving group in order to perform a nucleophilic substitution reaction on alcohols to produce more compounds. Hydroxide group is made a good leaving group by protonating the hydroxide group in the first step. After then the iodide ion attacks and eliminates protonated hydroxide group to halide product.

Conclusion

The completed reaction is shown in Figure 4.

Interpretation Introduction

(c)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

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

The ${\text{S}}_{\text{N}}\text{2}$ reaction is a nucleophilic substitution bimolecular reaction in which the addition of nucleophile and elimination of a leaving group takes place simultaneously. The rate of reaction depends upon both the substrate and reactant in the rate law equation.

Answer to Problem 10.59AP

The complete reaction is shown below.

The acid-base reaction between the thiol group and methoxide ion takes place first to give sulfide ion. The sulfide ion then reacts with methylating agent dimethyl sulfate to give the methylated product isopropyl(methyl) sulfane.

Explanation of Solution

The given reaction is shown below.

Figure 5

The complete reaction with the products is shown below.

Figure 6

The methoxide ion acts as a base and takes away the hydrogen of the thiol group of $\text{propane-2-thiol}$ to give the sulfide ion. This ion then reacts with the dimethyl sulfate to undergo methylation reaction to give the methylated product isopropyl(methyl) sulfane.

Conclusion

The completed reaction is shown in Figure 6.

Interpretation Introduction

(d)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

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

The ${\text{S}}_{\text{N}}\text{2}$ reaction is a nucleophilic substitution bimolecular reaction in which the addition of nucleophile and elimination of a leaving group takes place simultaneously. The rate of reaction depends upon both the substrate and reactant in the rate law equation.

Answer to Problem 10.59AP

The complete reaction is shown below.

This is an ${\text{S}}_{\text{N}}\text{2}$ reaction. Chloride group substitutes the hydroxide group.

Explanation of Solution

The given reaction is shown below.

Figure 7

The complete reaction with the products is shown below.

Figure 8

The reaction of alcohols with thionyl chloride is a ${\text{S}}_{\text{N}}\text{2}$ reaction. Chloride group substitutes the hydroxide group. Therefore, the $\text{4-phenylbutan-2-ol}$ reacts to give $\text{3-chlorobutylbenzene}$.

Conclusion

The completed reaction is shown in Figure 8.

Interpretation Introduction

(e)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

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

The ${\text{S}}_{\text{N}}\text{2}$ reaction is a nucleophilic substitution bimolecular reaction in which the addition of nucleophile and elimination of a leaving group takes place simultaneously. The rate of reaction depends upon both the substrate and reactant in the rate law equation.

Answer to Problem 10.59AP

The complete reaction is shown below.

This is an ${\text{S}}_{\text{N}}\text{2}$ reaction. Chloride group substitutes the hydroxide group and comes from the below the plane as the hydroxide group is above the plane.

Explanation of Solution

The given reaction is shown below.

Figure 9

The complete reaction with the products is shown below.

Figure 10

The reaction of alcohols with triphenylphosphine dichloride is a ${\text{S}}_{\text{N}}\text{2}$ reaction. Chloride group substitutes the hydroxide group. The stereochemistry of the product is inverted in ${\text{S}}_{\text{N}}\text{2}$ reaction. Therefore, chloride group goes below the plane.

Conclusion

The completed reaction is shown in Figure 10.

Interpretation Introduction

(f)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

An $\text{E2}$ reaction is a base-promoted $\beta -\text{elimination}$ reaction. This reaction follows a concerted reaction mechanism. In this reaction, a $\beta -$ proton is taken by the base and simultaneously leaving the group is eliminated. An alkene is obtained as a product of $\beta -\text{elimination}$ reaction.

Answer to Problem 10.59AP

The complete reaction is shown below.

The reaction between an alcohol and acid with heating undergoes dehydration reaction to give alkene as a product.

Explanation of Solution

The given reaction is shown below.

Figure 11

The complete reaction with the products is shown below.

Figure 12

The reaction of alcohols with acids and heat is an $\text{E2}$ reaction or dehydration reaction. The hydroxide is protonated at first and then the $\beta -$ proton anti to the protonated hydroxide is taken up by the conjugate base of acid and simultaneously removes the protonated hydroxide group to give the alkene as a product.

Conclusion

The completed reaction is shown in Figure 12.

Interpretation Introduction

(g)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

An $\text{E2}$ reaction is a base-promoted $\beta -\text{elimination}$ reaction. This reaction follows a concerted reaction mechanism. In this reaction, a $\beta -$ proton is taken by the base and simultaneously leaving the group is eliminated. An alkene is obtained as a product of $\beta -\text{elimination}$ reaction.

Answer to Problem 10.59AP

The complete reaction is shown below.

The first reaction is the nucleophilic substitution reaction of hydroxide group by the bromide ion. The second reaction is the elimination reaction in which strong base ${\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}\text{C}-{\text{O}}^{-}$ eliminates hydrogen bromide from the reactant to give alkene as a product.

Explanation of Solution

The given reaction is shown below.

Figure 13

The complete reaction with the products is shown below.

Figure 14

The first step of the reaction is a ${\text{S}}_{\text{N}}\text{2}$ reaction in which the bromide ion substitutes the protonated hydroxide group. In the second step, the strong and bulky base ${\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}\text{C}-{\text{O}}^{-}$ undergoes an $\text{E2}$ reaction and eliminates hydrogen bromide from the compound to give alkene product.

Conclusion

The completed reaction is shown in Figure 14.

Interpretation Introduction

(h)

Interpretation:

The given reaction is to be completed to give the principal products and to be explained.

Concept introduction:

An $\text{E2}$ reaction is a base-promoted $\beta -\text{elimination}$ reaction. This reaction follows a concerted reaction mechanism. In this reaction, a $\beta \text{-}$ proton is taken by the base and simultaneously leaving the group is eliminated. An alkene is obtained as a product of $\beta -\text{elimination}$ reaction.

Answer to Problem 10.59AP

The complete reaction is shown below.

The acid-base reaction between the thiol group and hydroxide ion takes place first to give sulfide ion. The sulfide ion then reacts with diethyl sulfane to give a mixture of thiol and disulfide.

Explanation of Solution

The given reaction is shown below.

Figure 15

The complete reaction with the products is shown below.

Figure 16

The hydroxide ion acts as a base and takes away the hydrogen of the thiol group of $\text{3-methyl-1-butanethiol}$ to give the sulfide ion. This ion then reacts with the diethyl sulfane to give a mixture of thiol and sulfane. The sulfide ion undergoes substitution reaction with the disulfides attacking at the one of the sulfur to give disulfide and thiol.

Conclusion

The completed reaction is shown in Figure 16.