Chapter 13, Problem 13.13P

Interpretation Introduction

(a)

Interpretation:

How the given compound can be synthesized from $\text{buta-1, 3-diene}$ is to be shown.

Concept introduction:

Electrophilic addition of a Bronsted acid to alkene proceeds via a carbocation intermediate. If the alkene is a conjugated diene, this means the carbocation is conjugated to a double bond and will exhibit resonance. This forms a mixture of products. One of the products is a $\text{1, 2-}$ adduct with the proton and the conjugate base of the acid added to adjacent carbons, formed from the carbocation initially produced. The other product is a $\text{1, 4-}$ adduct, formed from the resonance form of the carbocation. The major product is determined by the stability of the products. The $\text{1, 2-}$ adduct predominates at low temperatures, which means it is a kinetic product. The $\text{1, 4-}$ adduct predominates at higher temperatures, making it the thermodynamic product.

Interpretation Introduction

(b)

Interpretation:

How the given compound can be synthesized from $\text{buta-1, 3-diene}$ is to be shown.

Concept introduction:

Electrophilic addition of a Bronsted acid to alkene proceeds via a carbocation intermediate. If the alkene is a conjugated diene, this means the carbocation is conjugated to a double bond and will exhibit resonance. This forms a mixture of products. One of the products is a $\text{1, 2-}$ adduct, with the proton and the conjugate base of the acid added to adjacent carbons formed from the carbocation initially produced. The other product is a $\text{1, 4-}$ adduct formed from the resonance form of the carbocation. The major product is determined by the stability of the products. The $\text{1, 2-}$ adduct predominates at low temperatures, which means it is a kinetic product. The $\text{1, 4-}$ adduct predominates at higher temperatures making it the thermodynamic product.

Interpretation Introduction

(c)

Interpretation:

How the given compound can be synthesized from $\text{buta-1, 3-diene}$ is to be shown.

Concept introduction:

Electrophilic addition of a Bronsted acid to alkene proceeds via a carbocation intermediate. If the alkene is a conjugated diene, this means the carbocation is conjugated to a double bond and will exhibit resonance. This forms a mixture of products. One of the products is a $\text{1, 2-}$ adduct, with the proton and the conjugate base of the acid added to adjacent carbons formed from the carbocation initially produced. The other product is a $\text{1, 4-}$ adduct, formed from the resonance form of the carbocation. The major product is determined by the stability of the products. The $\text{1, 2-}$ adduct predominates at low temperatures, which means it is a kinetic product. The $\text{1, 4-}$ adduct predominates at higher temperatures making it the thermodynamic product.

A carbene, (${\text{H}}_{\text{2}}\text{C:}$) can be added to an alkene to introduce a cyclopropyl ring in the place of the $\text{π}$ bond. The carbene can be conveniently produced in situ by irradiating a mixture of diazomethane and the alkene with UV light.

Interpretation Introduction

(d)

Interpretation:

How the given compound can be synthesized from $\text{buta-1, 3-diene}$ is to be shown.

Concept introduction:

Electrophilic addition of a Bronsted acid to alkene proceeds via a carbocation intermediate. If the alkene is a conjugated diene, this means the carbocation is conjugated to a double bond and will exhibit resonance. This forms a mixture of products. One of the products is a $\text{1, 2-}$ adduct, with the proton and the conjugate base of the acid added to adjacent carbons formed from the carbocation initially produced. The other product is a $\text{1, 4-}$ adduct formed from the resonance form of the carbocation. The major product is determined by the stability of the products. The $\text{1, 2-}$ adduct predominates at low temperatures, which means it is a kinetic product. The $\text{1, 4-}$ adduct predominates at higher temperatures making it the thermodynamic product.