Chapter 20, Problem 20.43P

Interpretation Introduction

(a)

Interpretation: The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{NaBH}}_{\text{4}}$, ${\text{CH}}_{\text{3}}\text{OH}$ is to be predicted.

Concept introduction: The substitution reaction involves the replacement of one functional group by other functional group. In nucleophilic substitution an electron rich species attack the species that is deficient in electrons. The electrophile and the leaving group together form a substrate. The nucleophile attacks over the substrate and there occurs the removal of leaving group from the substrate.

Answer to Problem 20.43P

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{NaBH}}_{\text{4}}$, ${\text{CH}}_{\text{3}}\text{OH}$ is shown below.

Figure 1

Explanation of Solution

The reaction that shows the formation of product when $\text{α},\text{β}-$ unsaturated ketone reacts with ${\text{NaBH}}_{\text{4}}$, ${\text{CH}}_{\text{3}}\text{OH}$ is shown below.

Figure 2

In the given reaction, sodium borohydride is used as a reducing agent. Sodium borohydride is used for the reduction of carbonyl compounds to alcohols.

Conclusion

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{NaBH}}_{\text{4}}$, ${\text{CH}}_{\text{3}}\text{OH}$ is shown below.

Figure 1

Interpretation Introduction

(b)

Interpretation: The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{H}}_2\left(1\text{equiv}\right)$, $\text{Pd}-\text{C}$ is to be predicted.

Concept introduction: Addition of hydrogen takes place across a double bond of alkenes to form alkanes. This process is known as hydrogenation. It takes place in the presence of catalysts such as nickel, platinum or palladium.

Answer to Problem 20.43P

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{H}}_2\left(1\text{equiv}\right)$, $\text{Pd}-\text{C}$ is shown below.

Figure 3

Explanation of Solution

The reaction that shows the formation of product when $\text{α},\text{β}-$ unsaturated ketone reacts with ${\text{H}}_2\left(1\text{equiv}\right)$, $\text{Pd}-\text{C}$ is shown below.

Figure 4

In the given reaction, hydrogenation of alkene takes place in the presence of palladium.

Conclusion

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{H}}_2\left(1\text{equiv}\right)$, $\text{Pd}-\text{C}$ is shown below.

Figure 3

Interpretation Introduction

(c)

Interpretation: The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{H}}_2\left(\text{excess}\right)$, $\text{Pd}-\text{C}$ is to be predicted.

Concept introduction: Addition of hydrogen takes place across a double bond of alkenes to form alkanes. This process is known as hydrogenation. It takes place in the presence of catalysts such as nickel, platinum or palladium.

Answer to Problem 20.43P

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{H}}_2\left(\text{excess}\right)$, $\text{Pd}-\text{C}$ is shown below.

Figure 5

Explanation of Solution

The reaction that shows the formation of product when $\text{α},\text{β}-$ unsaturated ketone reacts with ${\text{H}}_2\left(\text{excess}\right)$, $\text{Pd}-\text{C}$ is shown below.

Figure 6

In the given reaction, excess hydrogen is used which will reduce both keto group and double bond. This results in the formation of a saturated compound.

Conclusion

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the ${\text{H}}_2\left(\text{excess}\right)$, $\text{Pd}-\text{C}$ is shown below.

Figure 5

Interpretation Introduction

(d)

Interpretation: The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[1\right]{\text{CH}}_{\text{3}}\text{Li}$;$\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is to be predicted.

Concept introduction: Methyllithium in the presence of water reduces carbonyl compounds into alcohol. Methyllithium is a reducing agent.

Answer to Problem 20.43P

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[1\right]{\text{CH}}_{\text{3}}\text{Li}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 7

Explanation of Solution

The reaction that shows the formation of product when $\text{α},\text{β}-$ unsaturated ketone reacts with $\left[1\right]{\text{CH}}_{\text{3}}\text{Li}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 8

The product formed in the given reaction is $1,2-$ addition product. The reagent used in this reaction is organolithium reagent. This reagent attacks on the carbonyl compound to form alkoxides. In the next step, protonation with water takes place to give the final product.

Conclusion

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[1\right]{\text{CH}}_{\text{3}}\text{Li}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 7

Interpretation Introduction

(e)

Interpretation: The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[\text{1}\right]{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ 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 20.43P

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[\text{1}\right]{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 9

Explanation of Solution

The reaction that shows the formation of product when $\text{α},\text{β}-$ unsaturated ketone reacts with $\left[\text{1}\right]{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 10

In the given reaction, Grignard reagent is used. This reagent attacks on the carbonyl compound to form alkoxides. In the next step, protonation with water takes place to give the final product.

Conclusion

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[\text{1}\right]{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 9

Interpretation Introduction

(f)

Interpretation: The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[\text{1}\right]{\left({\text{CH}}_{\text{2}}=\text{CH}\right)}_{\text{2}}\text{CuLi}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is to be predicted.

Concept introduction: The steps involved in the reaction of ketone with organolithium reagent are as follows:

• The first step involves the reduction of carbonyl group into single bonds.

• The second step is the addition of R group from organometallic reagent and hydrogen to oxygen.

Answer to Problem 20.43P

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[\text{1}\right]{\left({\text{CH}}_{\text{2}}=\text{CH}\right)}_{\text{2}}\text{CuLi}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 11

Explanation of Solution

The reaction that shows the formation of product when $\text{α},\text{β}-$ unsaturated ketone reacts with $\left[\text{1}\right]{\left({\text{CH}}_{\text{2}}=\text{CH}\right)}_{\text{2}}\text{CuLi}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 12

In the given reaction, organo copper reagent reacts with unsaturated carbonyl compound and forms carbon–carbon double bond with the beta carbon as shown in the above reaction.

Conclusion

The product formed when the $\text{α},\text{β}-$ unsaturated ketone A is treated with the $\left[\text{1}\right]{\left({\text{CH}}_{\text{2}}=\text{CH}\right)}_{\text{2}}\text{CuLi}$, $\left[\text{2}\right]{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 11