Chapter 21.7, Problem 45PTS

(a)

Interpretation Introduction

Interpretation:

To identify the major product in the given set of reactions when treated with ${\text{Et}}_{\text{2}}\text{CuLi}$ followed by mild acid.

Concept introduction:

The reaction between lithium dialkyl cuprate (Michael donor) which acts as a nucleophile for 1,4-conjugate addition to $\text{α, β-}$ unsaturated compound (Michael acceptor) is known as Michael reaction.  Michael reaction is thermodynamically controlled.  A general scheme is shown below,

The formed enolate when treated with alkyl halide installs the alkyl group in the $\text{α-}$ position.

(b)

Interpretation Introduction

Interpretation:

To identify the major product in the given set of reactions when treated with ${\text{Et}}_{\text{2}}\text{CuLi}$ followed by mild acid.

Concept introduction:

The reaction between lithium dialkyl cuprate (Michael donor) which acts as a nucleophile for 1,4-conjugate addition to $\text{α, β-}$ unsaturated compound (Michael acceptor) is known as Michael reaction.  Michael reaction is thermodynamically controlled.  A general scheme is shown below,

The formed enolate when treated with alkyl halide installs the alkyl group in the $\text{α}$ position.

Reduction of aldehyde to primary alcohol is done using $\text{LAH}$ followed by acid work-up.

(c)

Interpretation Introduction

Interpretation:

To identify the major product in the given set of reactions when treated with ${\text{Et}}_{\text{2}}\text{CuLi}$ followed by mild acid.

Concept introduction:

The reaction between lithium dialkyl cuprate (Michael donor) which acts as a nucleophile for 1,4-conjugate addition to $\text{α, β-}$ unsaturated compound (Michael acceptor) is known as Michael reaction.  Michael reaction is thermodynamically controlled.  A general scheme is shown below,

The formed enolate when treated with alkyl halide installs the alkyl group in the $\text{α}$ position.

Oxidation of the aldehyde with chromic acid gives the respective carboxylic acid which when treated with thionyl chloride gives the corresponding acid chloride.

(d)

Interpretation Introduction

Interpretation:

To identify the major product in the given set of reactions when treated with ${\text{Et}}_{\text{2}}\text{CuLi}$ followed by mild acid.

Concept introduction:

Hydrolysis of acetal with aqueous acid leads to ketone.

The reaction between lithium dialkyl cuprate (Michael donor) which acts as a nucleophile for 1,4-conjugate addition to $\text{α, β-}$ unsaturated compound (Michael acceptor) is known as Michael reaction.  Michael reaction is thermodynamically controlled.  A general scheme is shown below,

The formed enolate when treated with alkyl halide installs the alkyl group in the $\text{α}$ position.

When ketone is treated with ethylene glycol, the keto group is converted into an acetal.

(e)

Interpretation Introduction

Interpretation:

To identify the major product in the given set of reactions when treated with ${\text{Et}}_{\text{2}}\text{CuLi}$ followed by mild acid.

Concept introduction:

Alcohol when treated with $\text{PCC}$ undergoes oxidation to give aldehyde as the product.

The reaction between lithium dialkyl cuprate (Michael donor) which acts as a nucleophile for 1,4-conjugate addition to $\text{α, β-}$ unsaturated compound (Michael acceptor) is known as Michael reaction.  Michael reaction is thermodynamically controlled.  A general scheme is shown below,

The formed enolate when treated with alkyl halide installs the alkyl group in the $\text{α}$ position.

Imine is formed when aldehyde is treated with a primary amine in acidic condition.

(f)

Interpretation Introduction

Interpretation:

To identify the major product in the given set of reactions when treated with ${\text{Et}}_{\text{2}}\text{CuLi}$ followed by mild acid.

Concept introduction:

Alcohol when treated with $\text{PCC}$ undergoes oxidation to give aldehyde as the product.

The reaction between lithium dialkyl cuprate (Michael donor) which acts as a nucleophile for 1,4-conjugate addition to $\text{α, β-}$ unsaturated compound (Michael acceptor) is known as Michael reaction.  Michael reaction is thermodynamically controlled.  A general scheme is shown below,

The formed enolate when treated with alkyl halide installs the alkyl group in the $\text{α}$ position.

Clemmenson reduction of aldehyde gives alkane as the final product