Chapter 19.15, Problem 40PTS

(a)

Interpretation Introduction

Interpretation:

The mechanism for the following conversions has to be drawn.

                 

Concept Introduction:

Aromatic compounds undergo a special type of reaction called addition – elimination reactions. A compound with leaving group when treated with a strong base under high or low temperature undergoes elimination – addition reaction where the leaving group is eliminated and a new group is added.

(b)

Interpretation Introduction

Interpretation:

The mechanism for the following conversions has to be drawn.

                 

Concept Introduction:

• Electrophilic substitution reactions of aromatic compounds are known as aromatic electrophilic substitution reactions. An electrophile is a species that is deficient of electrons.

• Aromatic compounds agree with Huckel’s rule of aromaticity - cyclic, planar and have $\left(\text{4n+2}\right)\text{π}$ electrons. 

• Benzene and its related compounds undergo aromatic electrophilic substitution reactions since they are Aromatic compound. The delocalized nature of pi electrons in benzene attributes a special property to benzene called resonance.

• The various types of electrophilic substitution reactions in benzene are – Chlorination, Bromination, Nitration, Sulfonation, Friedel Crafts Alkylation/Acylation etc.

 (c)

Interpretation Introduction

Interpretation:

The mechanism for the following conversions has to be drawn.

                  

Concept Introduction:

• Apart from electrophilic substitution reactions benzene and its derivatives also undergo another special type of reactions namely Aromatic nucleophilic substitution reactions.

• The criteria for aromatic nucleophilic substitution reaction to occur are –

• The aromatic ring must contain a strong electron withdrawing group

• The aromatic ring must contain a leaving group

• The leaving group must be posited either ortho or para position to the strong electron withdrawing group.