Chapter 20, Problem 20.27P

Draw the products formed when each compound is treated with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ follwed by ${\text{H}}_{\text{2}}\text{O}$.

a. b. c.

Interpretation Introduction

(a)

Interpretation: The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is to be predicted.

Concept introduction: Grignard reagent is prepared by the reaction of alkyl or aryl bromide with magnesium metal in the presence of ether. The reaction of Grignard reagent with an aldehyde/ketone followed by hydrolysis yields an alcohol.

Answer to Problem 20.27P

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown below.

Explanation of Solution

The given compound is,

Figure 1

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 2

The first step involves the reaction of one equivalent of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ with the given compound which results in the formation of ketone. The next step is the formation of alkoxide by the reaction of one equivalent of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ with ketone. The last step is the protonation of alkoxide to form tertiary alcohol. Therefore, the product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is,

Figure 3

Conclusion

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown in Figure 3.

Interpretation Introduction

(b)

Interpretation: The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is to be predicted.

Concept introduction: Grignard reagent is prepared by the reaction of alkyl or aryl bromide with magnesium metal in the presence of ether. The reaction of Grignard reagent with an aldehyde/ketone followed by hydrolysis yields an alcohol.

Answer to Problem 20.27P

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown below.

Explanation of Solution

The given compound is,

Figure 4

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 5

The first step involves the reaction of one equivalent of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ with the given compound which results in the formation of ketone. The next step is the formation of alkoxide by the reaction of one equivalent of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ with ketone. The last step is the protonation of alkoxide to form tertiary alcohol. Therefore, the product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is,

Figure 6

Conclusion

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown in Figure 6.

Interpretation Introduction

(c)

Interpretation: The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is to be predicted.

Concept introduction: Grignard reagent is prepared by the reaction of alkyl or aryl bromide with magnesium metal in the presence of ether. The reaction of Grignard reagent with an aldehyde/ketone followed by hydrolysis yields an alcohol.

Answer to Problem 20.27P

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown below.

Explanation of Solution

The given compound is,

Figure 7

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 8

The first step involves the reaction of one equivalent of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ with the given compound which results in the formation of ketone. The next step is the formation of alkoxide by the reaction of one equivalent of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ with ketone. The last step is the protonation of alkoxide to form tertiary alcohol. Therefore, the product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is,

Figure 9

Conclusion

The product formed by the reaction of given compound with two equivalents of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{MgBr}$ followed by ${\text{H}}_{\text{2}}\text{O}$ is shown in Figure 9.