Chapter 22.11, Problem 26CC

 (a)

Interpretation Introduction

Interpretation: An efficient synthesis for the given transformations has to be proposed.

Concept Introduction:

Friedel-Crafts Alkylation: The Friedel-Crafts alkylation involves the electrophilic substitution of alkyl groups on aromatic rings when arenes are treated with alkyl halides in presence of Lewis acids.  This reaction is catalyzed by Lewis acids like anhydrous AlCl₃, FeX_3, ZnCl₂, BF₃ etc.

Sandmeyer reaction: Sandmeyer reactions use copper salts as the reagents.  Here, aryldiazonium salt is converted into aryl halides or aryl cyanides by using copper halides or copper cyanides.

A compound containing an amino group is treated with sodium nitrite and HCl leading to the formation of diazonium salt.

To find: Propose an efficient synthesis for the given transformation (a)

Decide the transformation

(b)

Interpretation Introduction

Interpretation: An efficient synthesis for the given transformations has to be proposed.

Concept Introduction:

Electrophilic aromatic substitution: Electrophilic aromatic substitution is a reaction in which the hydrogen atom of an aromatic ring is replaced as a result of an electrophilic attack on the aromatic ring.  Here are three general steps to an electrophilic aromatic substitution.

1. 1) Generation of an electrophile
2. 2) Attack of the electrophile on the aromatic ring, creating a resonance-stabilized carbocation called an arenium ion.   It loses aromaticity in this step, so the energy of activation is high. Furthermore, this is the rate-determining step of the reaction because of the disruption of aromaticity.  The arenium ion is a hybrid resonance structure. There are three general resonance contributors of an arenium ion.
3. 3) Deprotonation of the arenium ion by a weak base to regain aromaticity.

Sandmeyer reaction: Sandmeyer reactions use copper salts as the reagents.  Here, aryldiazonium salt is converted into aryl halides or aryl cyanides by using copper halides or copper cyanides.

A compound containing an amino group is treated with sodium nitrite and HCl leading to the formation of diazonium salt.

To find: Propose an efficient synthesis for the given transformation (b)

Apply a retrosynthetic analysis

(c)

Interpretation Introduction

Interpretation: An efficient synthesis for the given transformations has to be proposed.

Concept Introduction:

Friedel–Crafts Acylation: The Friedel–Crafts acylation is the reaction of an arene with acyl chlorides or anhydrides using a strong Lewis acid catalyst. This reaction proceeds via electrophilic aromatic substitution to form monoacylated products.

A compound containing an amino group is treated with sodium nitrite and HCl leading to the formation of diazonium salt.

To find: Propose an efficient synthesis for the given transformation (c)

Apply a retrosynthetic analysis

(d)

Interpretation Introduction

Interpretation: An efficient synthesis for the given transformations has to be proposed.

Concept Introduction:

Friedel-Crafts Alkylation: The Friedel-Crafts alkylation involves the electrophilic substitution of alkyl groups on aromatic rings when arenes are treated with alkyl halides in presence of Lewis acids.  This reaction is catalyzed by Lewis acids like anhydrous AlCl₃, FeX_3, ZnCl₂, BF₃ etc.

Sandmeyer reaction: Sandmeyer reactions use copper salts as the reagents.  Here, aryldiazonium salt is converted into aryl halides or aryl cyanides by using copper halides or copper cyanides.

A compound containing an amino group is treated with sodium nitrite and HCl leading to the formation of diazonium salt.

To find: Propose an efficient synthesis for the given transformation (d)

Apply a retrosynthetic analysis

(e)

Interpretation Introduction

Interpretation: An efficient synthesis for the given transformations has to be proposed.

Concept Introduction:

Electrophilic aromatic substitution: Electrophilic aromatic substitution is a reaction in which the hydrogen atom of an aromatic ring is replaced as a result of an electrophilic attack on the aromatic ring.  Here are three general steps to an electrophilic aromatic substitution.

1. 1) Generation of an electrophile
2. 2) Attack of the electrophile on the aromatic ring, creating a resonance-stabilized carbocation called an arenium ion.   It loses aromaticity in this step, so the energy of activation is high. Furthermore, this is the rate-determining step of the reaction because of the disruption of aromaticity.  The arenium ion is a hybrid resonance structure. There are three general resonance contributors of an arenium ion.
3. 3) Deprotonation of the arenium ion by a weak base to regain aromaticity.

Schiemann reaction: It is the reaction in which diazonium salt is converted into fluoro group using fluoroboric acid (HBF₄).

A compound containing an amino group is treated with sodium nitrite and HCl leading to the formation of diazonium salt.

To find: Propose an efficient synthesis for the given transformation (e)

Apply a retrosynthetic analysis

(f)

Interpretation Introduction

Interpretation: An efficient synthesis for the given transformations has to be proposed.

Concept Introduction:

Sandmeyer reaction: Sandmeyer reactions use copper salts as the reagents.  Here, aryldiazonium salt is converted into aryl halides or aryl cyanides by using copper halides or copper cyanides.

A compound containing an amino group is treated with sodium nitrite and HCl leading to the formation of diazonium salt.

To find: Propose an efficient synthesis for the given transformation (f)

Perform elimination-addition process