Chapter 20, Problem 20.39P

Draw the product formed when ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is treated with each compound. In some cases, no reaction occurs.

a. b. c. , then ${\text{H}}_{\text{2}}\text{O}$ d. , then ${\text{H}}_{\text{2}}\text{O}$

Interpretation Introduction

(a)

Interpretation: The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is to be drawn.

Concept introduction: Organometallic reagents like $\text{RLi,}\text{RMgX}$ and ${\text{R}}_{\text{2}}\text{CuLi}$ are the source of ${\text{R}}^{-}$, which acts as a nucleophile. Ketones on reaction with organometallic reagent convert into tertiary alcohol whereas aldehydes give primary and secondary alcohol.

Answer to Problem 20.39P

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is,

Figure 1

Explanation of Solution

Acid chlorides on reaction with organocuprate convert into ketone. The alkyl group of organocuprate occupies the position of leaving group $\left(\text{Cl}\right)$. Therefore, the product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is,

Figure 2

Conclusion

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is shown in Figure 2.

Interpretation Introduction

(b)

Interpretation: The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is to be drawn.

Concept introduction: Organometallic reagents like $\text{RLi,}\text{RMgX}$ and ${\text{R}}_{\text{2}}\text{CuLi}$ are the source of ${\text{R}}^{-}$, which acts as a nucleophile. Ketones on reaction with organometallic reagent convert into tertiary alcohol whereas aldehydes give primary and secondary alcohol.

Answer to Problem 20.39P

The given compound does not react with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$. Hence, no product is formed.

Explanation of Solution

Esters on reaction with two equivalents of organometallic reagent convert into tertiary alcohol. However, it does not react with organocuprate because organocuprate are less reactive than $\text{RLi}\text{and}\text{RMgX}$. Therefore, no product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$.

Conclusion

The given compound does not react with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$. Hence, no product is formed.

Interpretation Introduction

(c)

Interpretation: The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is to be drawn.

Concept introduction: Organometallic reagents like $\text{RLi,}\text{RMgX}$ and ${\text{R}}_{\text{2}}\text{CuLi}$ are the source of ${\text{R}}^{-}$, which acts as a nucleophile. Organocuprate reagent form $1,4$-addition product on reaction with $\text{α},\text{β}$-unsaturated carbonyl compound whereas organolithium and Grignard reagent form $1,2$-addition product on reaction with $\text{α},\text{β}$-unsaturated carbonyl compound.

Answer to Problem 20.39P

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is,

Figure 3

Explanation of Solution

Organocuprate reagent form $1,4$-addition product whereas organolithium reagent form $1,2$-addition product on reaction with $\text{α},\text{β}$-unsaturated carbonyl compound.

The product formed by the reaction of ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ with given $\text{α},\text{β}$-unsaturated carbonyl compound is $1,4$-addition product as shown in Figure 4.

Figure 4

Conclusion

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is shown in Figure 4.

Interpretation Introduction

(d)

Interpretation: The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is to be drawn.

Concept introduction: Organometallic reagents like $\text{RLi,}\text{RMgX}$ and ${\text{R}}_{\text{2}}\text{CuLi}$ are the source of ${\text{R}}^{-}$, which acts as a nucleophile. Ketones on reaction with organometallic reagent convert into tertiary alcohol whereas aldehydes give primary and secondary alcohol.

Answer to Problem 20.39P

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is,

Figure 5

Explanation of Solution

Epoxides are obtained by treating alkene with m-chloroperbenzoic acid $\left(m\text{CPBA}\right)$ and epoxides convert into alcohol when they are treated with organometallic reagents. The organometallic reagent, like organocuprate reagent, attacks on less substituted carbon atom of epoxide from backside.

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is shown in Figure 6.

Figure 6

Conclusion

The product formed by the treatment of given compound with ${\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\right)}_{\text{2}}\text{CuLi}$ is shown in Figure 6.