Chapter 8, Problem 8.46SP

(a)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 1.

The major product of the given reaction is shown in Figure 2.

Explanation of Solution

When $\text{2-methylbut-2-ene}$ reacts with $\text{HCl}$, it forms tertiary carbocation intermediate. The structure of an intermediate is given as,

Figure 1

The chloride ion acts as a nucleophile that attacks on the electrophilic tertiary carbocation and results in the formation of $\text{2-chloro-2-methylbutane}$. The addition of $\text{HCl}$ follows Markonikov’s rule as the chloride ion attacks at more substituted carbon atom.

The major product of the given reaction is,

Figure 2

(b)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 3.

The major product of the given reaction is shown in Figure 4.

Explanation of Solution

When $\text{1-methylcyclopent-1-ene}$ reacts with ${\text{Br}}_2$ in ${\text{CCl}}_{\text{4}}$, it forms a cyclic bromonium ion intermediate. The structure of an intermediate is given as,

Figure 3

Bromide ion opens the bromonium ion intermediate at the more substituted carbon atom and forms $\left(\text{1R,}\text{2R}\right)\text{-1,2-dibromo-1-methylcyclopentane}$. The major product of the given reaction is,

Figure 4

(c)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 5.

The major product of the given reaction is shown in Figure 6.

Explanation of Solution

When $\text{1-methylcyclopent-1-ene}$ reacts with diborane in the presence of THF, it forms borane. The addition of boron and hydrogen on double bond takes place on the same side of the double bond. The structure of an intermediate is given as,

Figure 5

When $\left(\text{2-methylcyclopentyl}\right)\text{borane}$ undergoes oxidation in the presence of ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}\text{,}{\text{OH}}^{-}$, it forms $\left(\text{1R,}\text{2R}\right)\text{-2-methylcyclopentanol}$. The hydroxyl group replaces the borane with same stereochemistry. The major product of the given reaction is,

Figure 6

(d)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 7.

The major product of the given reaction is shown in Figure 8.

Explanation of Solution

When $\left(\text{E}\right)\text{-3-methylpent-2-ene}$ reacts with ozone, it results in the formation of ozonide intermediate. The structure of an intermediate is given as,

Figure 7

Now, the ozonide intermediate reacts with dimethyl sulfide and forms acetaldehyde and $\text{but-2-one}$. The major product of the given reaction is,

Figure 8

(e)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 9.

Explanation of Solution

When alkene reacts with $\text{HBr}$ in the presence of peroxide, it forms anti Markonikov’s product and the mechanism undergoes free radical pathway. Here, ethylidenecyclohexane reacts with $\text{HBr}$ in the presence of peroxide to form $\left(\text{1-bromoethyl}\right)\text{cyclohexane}$. The major product of the given reaction is,

Figure 9

(f)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 10.

Explanation of Solution

When alkene reacts with $\text{HCl}$ in the presence of peroxide, it forms Markonikov’s product. It is due to the reaction of alkyl radical with $\text{HCl}$ which is an endothermic reaction. The major product of the given reaction is,

Figure 10

(g)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 11.

Explanation of Solution

When an alkene reacts with peroxyacid, it forms an epoxide or oxirane. Here, $\left(\text{E}\right)\text{-pent-2-ene}$ reacts with peroxybenzoic acid to form $\text{2-ethyl-3-methyloxirane}$.

The major product of the given reaction is,

Figure 11

(h)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 12.

The major product of the given reaction is shown in Figure 13.

Explanation of Solution

Alkene undergoes $\text{cis-hydroxylation}$ in the presence of ${\text{OsO}}_{\text{4}}$, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ to form cis-diols. Here, $\text{1-methylcyclopent-1-ene}$ reacts with ${\text{OsO}}_{\text{4}}$ and forms cyclic osmate ester.

The structure of an intermediate is given as,

Figure 12

Now, the cyclic osmate undergoes oxidation in the presence of ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ and forms $\left(\text{1S,2R}\right)\text{-1-methylcyclopentane-1,2-diol}$ and no change in stereochemistry takes place. The major product of the given reaction is,

Figure 13

(i)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 14.

Explanation of Solution

$\text{1-methylcyclopent-1-ene}$ reacts with cold dilute ${\text{KMnO}}_{\text{4}}$, ${\text{OH}}^{-}$ and forms $\left(\text{1S,2R}\right)\text{-1-methylcyclopent-1,2-diol}$. The two hydroxyl groups are added on the same side to the double bond that is the addition follows syn fashion.

The major product of the given reaction is,

Figure 14

(j)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 15.

The major product of the given reaction is shown in Figure 16.

Explanation of Solution

When an alkene reacts with peroxyacid, it forms an epoxide or oxirane. Here, $\text{1-methylcyclopent-1-ene}$ reacts with peroxyacetic acid to form $\text{oxirane}$.

The structure of an intermediate is given as,

Figure 15

The oxirane is opened at more substituted carbon atom in the presence of an acid ${\text{H}}^{+}$ and results in the formation of $\left(\text{1R,2R}\right)\text{-1-methylcyclopentane-1,2-diol}$.

The major product of the given reaction is,

Figure 16

(k)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 17.

Explanation of Solution

Alkene undergoes oxidative cleavage in the presence of hot concentrated ${\text{KMnO}}_{\text{4}}$, ${\text{OH}}^{-}$ and forms carbonyl compounds. Here, $\text{1-methylcyclohex-1-ene}$ undergoes oxidative cleavage in the presence of hot concentrated ${\text{KMnO}}_{\text{4}}$, ${\text{OH}}^{-}$ and results in the formation of $\text{6-oxoheptanoic}\text{acid}$.

The major product of the given reaction is,

Figure 17

(l)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 18.

Explanation of Solution

Alkene undergoes ozonolysis to form carbonyl compounds. Here, $\text{1-methylcyclohex-1-ene}$ undergoes an oxidative cleavage in the presence of ozone and ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ and forms $\text{6-oxaheptanal}$.

The major product of the given reaction is,

Figure 18

(m)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 19.

Explanation of Solution

In this reaction, $\text{1,2-methylcyclohex-1-ene}$ undergoes catalytic reduction in the presence of ${\text{H}}_{\text{2}}\text{,}\text{Pt}$ and forms $\left(\text{1R,2S}\right)\text{-1,2-dimethylcyclohexane}$.

The major product of the given reaction is,

Figure 19

(n)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate and the major product of the given reaction are shown in Figure 20.

Explanation of Solution

This reaction is an acid catalyzed hydration of alkene and forms $\text{decahydronapthalene-4a-ol}$.

The structure of an intermediate and the major product of the given reaction is,

Figure 20

(o)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The major product of the given reaction is shown in Figure 21.

Explanation of Solution

The given reaction is an olefin metathesis. The major product of the given reaction is,

Figure 21

(p)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 22.

The major product of the given reaction is shown in Figure 24.

Explanation of Solution

Alkene reacts with mercuric acetate and forms mercurinium ion intermediate.

The structure of an intermediate is given as,

Figure 22

Now, water molecule acts as a nucleophile that opens the mercurinium ion at the most substituted carbon atom.

Figure 23

Now, organomercurial alcohol undergoes demercuration in the presence of ${\text{NaBH}}_{\text{4}}$ and forms $\text{decahydronapthalene-4a-ol}$. The major product of the given reaction is,

Figure 24

(q)

Interpretation Introduction

Interpretation:

The major product of the given reaction and the structure of any intermediate are to be predicted.

Concept introduction:

Substitution reactions are the reactions in which there is a replacement of an atom or a functional group by another atom or a functional group.

Elimination reactions are the reaction in which alkenes are prepared. In this two substituents are eliminated by either one step or two step mechanism.

Answer to Problem 8.46SP

The structure of an intermediate is shown in Figure 25.

The major product of the given reaction is shown in Figure 26.

Explanation of Solution

Alkene reacts with chlorine and forms chloronium ion intermediate.

The structure of an intermediate is given as,

Figure 25

Now, the water molecule acts as a nucleophile that opens the chloronium ion intermediate at more substituted carbon atom. The major product of the given reaction is,

Figure 26