Chapter 18, Problem 18.46AP

Interpretation Introduction

(a)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_{\text{3}}\text{OH}$ is to be stated.

Concept introduction:

The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron rich chemical species that contains negative charge or lone pair of electrons are known as nucleophile. In nucleophilc acyl substitution reaction, nucleophile takes the position of leaving group.

Answer to Problem 18.46AP

No product is formed on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_{\text{3}}\text{OH}$.

Explanation of Solution

The reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_{\text{3}}\text{OH}$ is shown below.

Figure 1

Aryl iodides cannot undergo nucleophilic substitution reaction. Aryl iodides neither undergo ${\text{S}}_{\text{N}}\text{2}$ reaction due to the inability of attack on backside nor do they undergo ${\text{S}}_{\text{N}}\text{1}$ reaction as a carbocation cannot be formed.

Conclusion

There is no product formed on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_{\text{3}}\text{OH}$.

Interpretation Introduction

(b)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$ in ${\text{CH}}_{\text{3}}\text{OH}$ is to be stated.

Concept introduction:

The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron rich chemical species that contains negative charge or lone pair of electrons are known as nucleophile. In nucleophilc acyl substitution reaction, nucleophile takes the position of leaving group.

Answer to Problem 18.46AP

No product is formed on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$ in ${\text{CH}}_{\text{3}}\text{OH}$.

Explanation of Solution

The reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$ in ${\text{CH}}_{\text{3}}\text{OH}$ is shown below.

Figure 2

Aryl iodides cannot undergo nucleophilic substitution reaction. Aryl iodides neither undergo ${\text{S}}_{\text{N}}\text{2}$ reaction due to the inability of attack on backside nor do they undergo ${\text{S}}_{\text{N}}\text{1}$ reaction as a carbocation cannot be formed.

Conclusion

There is no product formed on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$ in ${\text{CH}}_{\text{3}}\text{OH}$.

Interpretation Introduction

(c)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$ in presence of pressure and heat is to be stated.

Concept introduction:

The replacement or substitution of one functional group with another different functional group in any chemical reaction is termed as substitution reaction. The electron rich chemical species that contains negative charge or lone pair of electrons are known as nucleophile. In nucleophilc acyl substitution reaction, nucleophile takes the position of leaving group.

Answer to Problem 18.46AP

No product is formed on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$.

Explanation of Solution

The product on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$ is shown below.

Figure 3

Aryl iodides cannot undergo nucleophilic substitution reaction. Aryl iodides neither undergo ${\text{S}}_{\text{N}}\text{2}$ reaction due to the inability of attack on backside nor do they undergo ${\text{S}}_{\text{N}}\text{1}$ reaction as a carbocation cannot be formed.

Conclusion

There is no product formed on reaction of $p-\text{iodotoluene}$ with ${\text{CH}}_3{\text{O}}^{-}$.

Interpretation Introduction

(d)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with $\text{Mg}$ in THF is to be stated.

Concept introduction:

Grignard reagents are organometallic compounds which are prepared using alkyl halides in presence of magnesium metal in dry ether. These reagents act as strong nucleophiles and bases.

Answer to Problem 18.46AP

The product on reaction of $p-\text{iodotoluene}$ with $\text{Mg}$ in THF is shown below.

Explanation of Solution

The reaction of $p-\text{iodotoluene}$ with $\text{Mg}$ in THF is shown below.

Figure 4

In the above reaction, magnesium gets inserted in the carbon-halogen bond to form a Grignard reagent. THF is used as the reaction should be done in anhydrous and inert condition. Therefore, the product formed on reaction of $p-\text{iodotoluene}$ with $\text{Mg}$ in THF is shown below.

Figure 5

Conclusion

The reaction of $p-\text{iodotoluene}$ with $\text{Mg}$ in THF is shown in Figure 5.

Interpretation Introduction

(e)

Interpretation:

The product on reaction of the product formed in part (d) with $\text{ClSn}{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}$ is to be stated.

Concept introduction:

Stille reaction is an example of coupling reaction. In Stille reaction, the triflate reacts with trimethylstannane in presence of $\text{Pd}$ catalyst and $\text{LiCl}$ to give a coupled product of hydrocarbon part of trimethylstannane and triflate.

Answer to Problem 18.46AP

The product on reaction of the product formed in part (d) with $\text{ClSn}{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}$ is shown below.

Explanation of Solution

The product formed in part (d) is shown below.

Figure 5

The reaction of the product formed in part (d) with $\text{ClSn}{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}$ is shown below.

Figure 6

In the above reaction, a stannane compound is formed on reaction of a Grignard reagent with $\text{ClSn}{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}$. The reaction is known as a Stille coupling reaction. It involves the formation of a carbon-carbon bond. Therefore, the product on reaction of the product formed in part (d) with $\text{ClSn}{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}$ is shown below.

Figure 7

Conclusion

The product on reaction of the product formed in part (d) with $\text{ClSn}{\left({\text{CH}}_{\text{3}}\right)}_{\text{3}}$ is shown in Figure 7.

Interpretation Introduction

(f)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with $\text{Li}$ in hexane is to be stated.

Concept introduction:

Alkyl lithium is an organolithium reagent. It contains carbon-lithium bond. It is used in organic synthesis and to transfer an organic group to substrate. Halo compounds on reaction with lithium under inert conditions tend to form carbon-lithium bond. The reaction in which a halo group is lost and a new carbon-lithium bond is formed is known as lithium-halogen exchange reaction.

Answer to Problem 18.46AP

The product on reaction of $p-\text{iodotoluene}$ with $\text{Li}$ in hexane is shown below.

Explanation of Solution

The reaction of $p-\text{iodotoluene}$ with $\text{Li}$ in hexane is shown below.

Figure 8

The above reaction is known as lithium-halogen exchange reaction. The reaction occurs under inert conditions. In this reaction, two moles of lithium react with $p-\text{iodotoluene}$ to form a carbon-lithium bond and one mole of lithium iodide is formed as side product. Therefore, the product formed on reaction of $p-\text{iodotoluene}$ with $\text{Li}$ in hexane is shown below.

Figure 9

Conclusion

The product on reaction of $p-\text{iodotoluene}$ with $\text{Li}$ in hexane is shown in Figure 9.

Interpretation Introduction

(g)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with ${\text{H}}_{\text{2}}{\text{C=CH}}_2,\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst, and ${\left(\text{Et}\right)}_3\text{N:}$ in ${\text{CH}}_{\text{3}}\text{CN}$ is to be stated.

Concept introduction:

The treatment of an organic halide with an alkene in the presence of $\text{Pd}$ catalyst to form an alkene that is highly substituted with a new $\text{C}-\text{C}$ bond is known as Heck reaction. Generally $\left[\text{Pd}{\left(\text{OAc}\right)}_2\right]$ in the presence of $\left[\text{P}{\left(o\text{-tolyl}\right)}_3\right]$ is utilized as catalyst. The reaction is carried out in the presence of organic base, like ${\text{Et}}_{\text{3}}\text{N}$.

Answer to Problem 18.46AP

The product on reaction of $p-\text{iodotoluene}$ with ${\text{H}}_{\text{2}}{\text{C=CH}}_2,\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst, and ${\left(\text{Et}\right)}_3\text{N:}$ in ${\text{CH}}_{\text{3}}\text{CN}$ is shown below.

Explanation of Solution

The reaction of $p-\text{iodotoluene}$ with ${\text{H}}_{\text{2}}{\text{C=CH}}_2,\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst, and ${\left(\text{Et}\right)}_3\text{N:}$ in ${\text{CH}}_{\text{3}}\text{CN}$ is shown below.

Figure 10

In the above reaction a coupled product is formed. The coupling takes place between ethene and $p-\text{iodotoluene}$ in presence of $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst and base like ${\left(\text{Et}\right)}_3\text{N:}$. This reaction is also known as Heck reaction. Therefore, the product formed on reaction of $p-\text{iodotoluene}$ with ${\text{H}}_{\text{2}}{\text{C=CH}}_2,\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst, and ${\left(\text{Et}\right)}_3\text{N:}$ in ${\text{CH}}_{\text{3}}\text{CN}$ is shown below.

Figure 11

Conclusion

The product on reaction of $p-\text{iodotoluene}$ with ${\text{H}}_{\text{2}}{\text{C=CH}}_2,\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst, and ${\left(\text{Et}\right)}_3\text{N:}$ in ${\text{CH}}_{\text{3}}\text{CN}$ is shown in Figure 11.

Interpretation Introduction

(h)

Interpretation:

The product on reaction of product of part (e) with phenyl triflate, excess $\text{LiCl}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst in dioxane is to be stated.

Concept introduction:

Stille reaction is an example of coupling reaction. In Stille reaction, the triflate reacts with trimethylstannane in presence of $\text{Pd}$ catalyst and $\text{LiCl}$ to give a coupled product of hydrocarbon part of trimethylstannane and triflate.

Answer to Problem 18.46AP

The product on reaction of product of part (e) with phenyl triflate, excess $\text{LiCl}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst in dioxane is shown below.

Explanation of Solution

The product formed in part (e) is shown below.

Figure 7

The reaction of above compound with phenyl triflate, excess $\text{LiCl}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst in dioxane is shown below.

Figure 12

The above reaction is an example of Stille coupling reaction. In this reaction a triflate reacts with stannane compound in presence of $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ as catalyst to give a coupled product. The coupling occurs between triflate and stannane compound to form a biphenyl. Therefore, the product on reaction of product of part (e) with phenyl triflate, excess $\text{LiCl}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst in dioxane is shown below.

Figure 13

Conclusion

The product on reaction of product of part (e) with phenyl triflate, excess $\text{LiCl}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst in dioxane is shown in Figure 13.

Interpretation Introduction

(i)

Interpretation:

The product on reaction of $p-\text{iodotoluene}$ with $\text{PhB}{\left(\text{OH}\right)}_{\text{2}}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is to be stated.

Concept introduction:

The Suzuki coupling reaction is a reaction in which an aryl or vinylic boronic acid is coupled to an aryl or vinylic iodide or bromide. It is a $\text{Pd}\left(0\right)$ catalysed reaction. This reaction can be used to prepare biaryls, aryl-substituted alkenes, and conjugated alkenes.

Answer to Problem 18.46AP

The product on reaction of $p-\text{iodotoluene}$ with $\text{PhB}{\left(\text{OH}\right)}_{\text{2}}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown below.

Explanation of Solution

The reaction of $p-\text{iodotoluene}$ with $\text{PhB}{\left(\text{OH}\right)}_{\text{2}}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown below.

Figure 14

In the above reaction, $p-\text{iodotoluene}$ reacts with phenylboronic acid to form a coupled product. The coupling occurs between phenylboronic acid and $p-\text{iodotoluene}$ to form a new carbon-carbon bond. This results in the formation of a biphenyl. This reaction is known as Suzuki coupling reaction. Therefore, the product on reaction of $p-\text{iodotoluene}$ with $\text{PhB}{\left(\text{OH}\right)}_{\text{2}}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown below.

Figure 15

Conclusion

The product on reaction of $p-\text{iodotoluene}$ with $\text{PhB}{\left(\text{OH}\right)}_{\text{2}}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown in Figure 15.

Interpretation Introduction

(j)

Interpretation:

The product on reaction of product of part (d) with $\text{B}{\left({\text{OCH}}_{\text{3}}\right)}_{\text{3}}$, then ${\text{H}}_{\text{3}}{\text{O}}^{+}/{\text{H}}_2\text{O}$ is to be stated.

Concept introduction:

The Suzuki coupling reaction in which an aryl or vinylic boronic acid is coupled to an aryl or vinylic iodide or bromide. It is a $\text{Pd}\left(0\right)$ catalyzed reaction. This reaction can be used to prepare biaryls, aryl-substituted alkenes, and conjugated alkenes.

Answer to Problem 18.46AP

The product of part (d) with $\text{B}{\left({\text{OCH}}_{\text{3}}\right)}_{\text{3}}$, then ${\text{H}}_{\text{3}}{\text{O}}^{+}/{\text{H}}_2\text{O}$ is shown below.

Explanation of Solution

The product of part (d) is shown below.

Figure 5

The reaction of product of part (d) with $\text{B}{\left({\text{OCH}}_{\text{3}}\right)}_{\text{3}}$, then ${\text{H}}_{\text{3}}{\text{O}}^{+}/{\text{H}}_2\text{O}$ is shown below.

Figure 16

In the above reaction, $p-\text{tolylmagnesium}\text{iodide}$ reacts with $\text{B}{\left({\text{OCH}}_{\text{3}}\right)}_{\text{3}}$ followed by hydrolysis to give boronic acid. This reaction is an example of Suzuki reaction. Therefore, the product of part (d) with $\text{B}{\left({\text{OCH}}_{\text{3}}\right)}_{\text{3}}$, then ${\text{H}}_{\text{3}}{\text{O}}^{+}/{\text{H}}_2\text{O}$ is shown below.

Figure 17

Conclusion

The product of part (d) with $\text{B}{\left({\text{OCH}}_{\text{3}}\right)}_{\text{3}}$, then ${\text{H}}_{\text{3}}{\text{O}}^{+}/{\text{H}}_2\text{O}$ is shown in Figure 17.

Interpretation Introduction

(k)

Interpretation:

The product on reaction of product of part (j) with $\left(E\right)-1-\text{bromopropene}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is to be stated.

Concept introduction:

The Suzuki coupling reaction in which an aryl or vinylic boronic acid is coupled to an aryl or vinylic iodide or bromide. It is a $\text{Pd}\left(0\right)$ catalysed reaction. This reaction can be used to prepare biaryls, aryl-substituted alkenes, and conjugated alkenes.

Answer to Problem 18.46AP

The product on reaction of product of part (j) with $\left(E\right)-1-\text{bromopropene}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown below.

Explanation of Solution

The product of part (j) is shown below.

Figure 17

The reaction of product of part (j) with $\left(E\right)-1-\text{bromopropene}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown below.

Figure 18

The above reaction is Suzuki coupling reaction. In this reaction, $p-\text{tolylboronic}\text{acid}$ reacts with the given alkyne in presence of sodium carbonate and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst to give a coupled product. Therefore, the product of part (j) with $\left(E\right)-1-\text{bromopropene}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown below.

Figure 19

Conclusion

The product on reaction of product of part (j) with $\left(E\right)-1-\text{bromopropene}$, aqueous ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$, and $\text{Pd}{\left({\text{PPh}}_{\text{3}}\right)}_{\text{4}}$ catalyst is shown in Figure 19.