Chapter 23, Problem 23.51P

Interpretation Introduction

(a)

Interpretation:

Whether the given compound can undergo a Friedel–Crafts reaction, it is to be determined.

Concept introduction:

The Friedel–Crafts reaction is the electrophilic aromatic substitution reaction. In The Friedel–Crafts alkylation, the aromatic compound reacts with alkyl halide in presence of ${\text{AlCl}}_{\text{3}}$ where the alkyl group gets attached to aromatic ring. The Friedel–Crafts reactions do not readily take place on moderately or strongly deactivated aromatic rings. The electron donating groups increases the electron density around the ring and activates it whereas the electron withdrawing groups decrease the electron density around the ring and deactivates it.

Answer to Problem 23.51P

The given compound can undergo a Friedel–Crafts reaction as the aromatic ring is activated by two methyl groups.

Explanation of Solution

The given aromatic compound is:

In this aromatic compound, the benzene ring has two methyl groups attached. The alkyl groups are electron donating inductively, thus increases the electron density around the ring and activates it. As the ring is electron rich and activated it can undergo Friedel–Crafts reaction.

Conclusion

It is determined that a given compound can undergo Friedel–Crafts reaction based on the activation of aromatic ring.

Interpretation Introduction

(b)

Interpretation:

Whether the given compound can undergo a Friedel–Crafts reaction, it is to be determined.

Concept introduction:

The Friedel–Crafts reaction is the electrophilic aromatic substitution reaction. In The Friedel–Crafts alkylation, the aromatic compound reacts with alkyl halide in presence of ${\text{AlCl}}_{\text{3}}$ where the alkyl group gets attached to aromatic ring. The Friedel–Crafts reactions do not readily take place on moderately or strongly deactivated aromatic rings. The electron donating groups increases the electron density around the ring and activates it whereas the electron withdrawing groups decrease the electron density around the ring and deactivates it.

Answer to Problem 23.51P

The given compound cannot undergo a Friedel–Crafts reaction as the aromatic ring is deactivated by two acetyl groups.

Explanation of Solution

The given aromatic compound is:

In this aromatic compound, the benzene ring has two acetyl (carbonyl) groups attached. The carbonyl groups have electron withdrawing resonance effect, thus decreases the electron density around the ring and deactivates it. As the ring is electron poor and deactivated it cannot undergo Friedel–Crafts reaction.

Conclusion

It is determined that a given compound cannot undergo Friedel–Crafts reaction based on the deactivation of aromatic ring.

Interpretation Introduction

(c)

Interpretation:

Whether the given compound can undergo a Friedel–Crafts reaction, it is to be determined.

Concept introduction:

The Friedel–Crafts reaction is the electrophilic aromatic substitution reaction. In The Friedel–Crafts alkylation, the aromatic compound reacts with alkyl halide in presence of ${\text{AlCl}}_{\text{3}}$ where the alkyl group gets attached to aromatic ring. The Friedel–Crafts reactions do not readily take place on moderately or strongly deactivated aromatic rings. The electron donating groups increases the electron density around the ring and activates it whereas the electron withdrawing groups decrease the electron density around the ring and deactivates it.

Answer to Problem 23.51P

The given compound cannot undergo a Friedel–Crafts reaction as the aromatic ring is deactivated by nitrile groups.

Explanation of Solution

The given aromatic compound is:

In this aromatic compound, the benzene ring has nitrile group attached. The nitrile group have electron withdrawing resonance effect, thus decreases the electron density around the ring and deactivates it. As the ring is electron poor and deactivated it cannot undergo Friedel–Crafts reaction.

Conclusion

It is determined that a given compound cannot undergo Friedel–Crafts reaction based on the deactivation of aromatic ring.

Interpretation Introduction

(d)

Interpretation:

Whether the given compound can undergo a Friedel–Crafts reaction, it is to be determined.

Concept introduction:

The Friedel–Crafts reaction is the electrophilic aromatic substitution reaction. In The Friedel–Crafts alkylation, the aromatic compound reacts with alkyl halide in presence of ${\text{AlCl}}_{\text{3}}$ where the alkyl group gets attached to aromatic ring. The Friedel–Crafts reactions do not readily take place on moderately or strongly deactivated aromatic rings. The electron donating groups increases the electron density around the ring and activates it whereas the electron withdrawing groups decrease the electron density around the ring and deactivates it.

Answer to Problem 23.51P

The given compound cannot undergo a Friedel–Crafts reaction as the aromatic ring is deactivated by ${\text{SO}}_{\text{3}}\text{H}$ group.

Explanation of Solution

The given aromatic compound is:

In this aromatic compound, the benzene ring has ${\text{SO}}_{\text{3}}\text{H}$ group and methyl group attached. The ${\text{SO}}_{\text{3}}\text{H}$ group have electron withdrawing resonance effect, and the methyl has electron donating inductive effect. The resonance effect is predominant over inductive effect thus decreases the electron density around the ring and strongly deactivates it. As the ring is electron poor and deactivated it cannot undergo Friedel–Crafts reaction.

Conclusion

It is determined that a given compound cannot undergo Friedel–Crafts reaction based on the deactivation of aromatic ring.

Interpretation Introduction

(e)

Interpretation:

Whether the given compound can undergo a Friedel–Crafts reaction, it is to be determined.

Concept introduction:

The Friedel–Crafts reaction is the electrophilic aromatic substitution reaction. In The Friedel–Crafts alkylation, the aromatic compound reacts with alkyl halide in presence of ${\text{AlCl}}_{\text{3}}$ where the alkyl group gets attached to aromatic ring. The Friedel–Crafts reactions do not readily take place on moderately or strongly deactivated aromatic rings. The electron donating groups increases the electron density around the ring and activates it whereas the electron withdrawing groups decrease the electron density around the ring and deactivates it.

Answer to Problem 23.51P

The given compound cannot undergo a Friedel–Crafts reaction as the aromatic ring is deactivated by ${\text{SO}}_{\text{3}}\text{H}$ group and chlorine atom.

Explanation of Solution

The given aromatic compound is:

In this aromatic compound, the benzene ring has ${\text{SO}}_{\text{3}}\text{H}$ group and chlorine attached. The both ${\text{SO}}_{\text{3}}\text{H}$ group has electron withdrawing resonance effect and the chlorine has electron withdrawing inductive effect, thus decreases the electron density around the ring and strongly deactivates it. As the ring is electron poor and deactivated it cannot undergo Friedel–Crafts reaction.

Conclusion

It is determined that a given compound cannot undergo Friedel–Crafts reaction based on the deactivation of aromatic ring.

Interpretation Introduction

(f)

Interpretation:

Whether the given compound can undergo a Friedel–Crafts reaction, it is to be determined.

Concept introduction:

The Friedel–Crafts reaction is the electrophilic aromatic substitution reaction. In The Friedel–Crafts alkylation, the aromatic compound reacts with alkyl halide in presence of ${\text{AlCl}}_{\text{3}}$ where the alkyl group gets attached to aromatic ring. The Friedel–Crafts reactions do not readily take place on moderately or strongly deactivated aromatic rings. The electron donating groups increases the electron density around the ring and activates it whereas the electron withdrawing groups decrease the electron density around the ring and deactivates it.

Answer to Problem 23.51P

The given compound can undergo a Friedel–Crafts reaction as the aromatic ring is activated by one methyl and one methoxy groups.

Explanation of Solution

The given aromatic compound is:

In this aromatic compound, the benzene ring has one methyl and one methoxy groups attached. The alkyl groups are electron donating inductively and methoxy group has electron donating resonance effect, thus increases the electron density around the ring and activates it. As the ring is electron rich and activated it can undergo Friedel–Crafts reaction.

Conclusion

It is determined that a given compound can undergo Friedel–Crafts reaction based on the activation of aromatic ring.