Chapter 17, Problem 17.22AP

Interpretation Introduction

(a)

Interpretation:

The principal organic compound that is expected when $trans\text{-2-butene}$ is reacted with ${\text{Br}}_{\text{2}}$ in ${\text{CH}}_{\text{2}}{\text{Cl}}_{\text{2}}$, dark is to be stated.

Concept introduction:

The addition reaction of the alkene are very well known reactions. The electron density on the alkene double bond makes it nucleophilic. The alkene undergoes varieties of addition reaction via different mechanisms.

Answer to Problem 17.22AP

The principal organic compound that is formed when $trans\text{-2-butene}$ is reacted with ${\text{Br}}_{\text{2}}$ in ${\text{CH}}_{\text{2}}{\text{Cl}}_{\text{2}}$, dark is shown below.

Explanation of Solution

The reaction of $trans\text{-2-butene}$ when reacted with ${\text{Br}}_{\text{2}}$ in ${\text{CH}}_{\text{2}}{\text{Cl}}_{\text{2}}$, dark is shown below.

Figure 1

The addition of the bromine molecule on the double bond of the alkene takes place to give the dibromo product. The addition of bromine to the double bond is the anti-addition.

Conclusion

The principal organic compound that is formed when $trans\text{-2-butene}$ is reacted with ${\text{Br}}_{\text{2}}$ in ${\text{CH}}_{\text{2}}{\text{Cl}}_{\text{2}}$, dark is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The principal organic compound that is expected when $trans\text{-2-butene}$ is reacted N-bromosuccinimide in ${\text{CCl}}_{\text{4}}$, light is to be stated.

Concept introduction:

The addition reactions of the alkene are very well known reactions. The electron density on the alkene double bond makes it nucleophilic. The alkene undergoes varieties of addition reaction via different mechanisms.

Answer to Problem 17.22AP

The principal organic compound that is formed when $trans\text{-2-butene}$ is reacted with N-bromosuccinimide in ${\text{CCl}}_{\text{4}}$, light is shown below.

Explanation of Solution

The reaction of $trans\text{-2-butene}$ when reacted with N-bromosuccinimide in ${\text{CCl}}_{\text{4}}$, light is shown below.

Figure 2

The reaction of an alkene with N-bromosuccinimide in the presence is the free-radical reaction. In this reaction, allylic bromination is observed instead of an addition to the alkene. The N-bromosuccinimide acts as radical initiator. This molecule breaks the $\text{N}-\text{Br}$ bond homolytically to give bromine radical. The bromine takes up the allylic hydrogen and leads to the formation of the allylic carbocation. The allylic carbocation is resonance stabilized and leads to the formation of two resonating structures. These two resonating structures than reacts with bromine molecule produced in the reaction to give the allylic brominated products for both resonating structures.

Conclusion

The principal organic compound that is formed when $trans\text{-2-butene}$ is reacted with N-bromosuccinimide in ${\text{CCl}}_{\text{4}}$, light is shown in Figure 2.

Interpretation Introduction

(c)

Interpretation:

The principal organic compound that is expected when product(s) of part (b) undergo solvolysis in aqueous acetone is to be stated.

Concept introduction:

The nucleophilic substitution reactions are the reactions in which a group is substituted by a nucleophile. The rate of reaction depends 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 17.22AP

The principal organic compounds that are formed when product(s) of part (b) undergo solvolysis in aqueous acetone are shown below.

Explanation of Solution

The products of part (b) are shown below.

Figure 3

The reaction when product(s) of part (b) undergo solvolysis in aqueous acetone is shown below.

Figure 4

The nucleophilic substitution reaction takes place when solvolysis of products of part (b) takes place. The bromine group is substituted by the hydroxyl group giving rise to the formation of an allylic alcohol.

Conclusion

The principal organic compound that is formed when product(s) of part (b) undergo solvolysis in aqueous acetone is shown in Figure 4.

Interpretation Introduction

(d)

Interpretation:

The principal organic compound that is expected when product(s) of part (b) are reacted with $\text{Mg}$ in ether is to be stated.

Concept introduction:

The reaction of an alkyl halide with a metal-like magnesium in the presence of dry ether leads to the formation of $\text{RMgX}$ (organometallic compounds) also known as a Grignard reagent. These compounds are very sensitive to moisture or polar hydrogens reacts immediately leading to the formation of alkane of the alkyl group.

Answer to Problem 17.22AP

The principal organic compounds that are formed when product(s) of part (b) are reacted with $\text{Mg}$ in ether is shown below.

Explanation of Solution

The products of part (b) are shown below.

Figure 3

The reaction that occurs when product(s) of part (b) are reacted with $\text{Mg}$ in ether is shown below.

Figure 5

The allylic halide also undergoes the same kind of reactions are do the alkyl halide with magnesium metal in dry ether. They are also lead to the formation of Grignard reagent but this time with the allylic group.

Conclusion

The principal organic compound that is formed when product(s) of part (b) undergo solvolysis in aqueous acetone is shown in Figure 5.

Interpretation Introduction

(e)

Interpretation:

The principal organic compound that is expected when product(s) of part (d) are reacted with ${\text{D}}_{\text{2}}\text{O}$ is to be stated.

Concept introduction:

The reaction of an alkyl halide with a metal-like magnesium in the presence of dry ether leads to the formation of $\text{RMgX}$ (organometallic compounds) also known as a Grignard reagent. These compounds are very sensitive to moisture or polar hydrogens reacts immediately leading to the formation of alkane of the alkyl group.

Answer to Problem 17.22AP

The principal organic compound that is formed when products of part (d) react with ${\text{D}}_{\text{2}}\text{O}$ is shown shown below.

Explanation of Solution

The products of part (d) are shown below.

Figure 6

The Gringnard reagents react with ${\text{D}}_{\text{2}}\text{O}$ to from deuterated alkenes. The $-\text{MgBr}$ groups are get replaced by $-\text{D}$. The corresponding chemical reaction is shown below.

Figure 7

Conclusion

The principal organic compound that is formed when products of part (d) react with ${\text{D}}_{\text{2}}\text{O}$ is shown in Figure 7.