Chapter 23, Problem 23.5P

Interpretation Introduction

(a)

Interpretation:

The mechanism that leads to the ortho-, meta-, and para-disubstituted products for the given reaction is to be drawn and major products are to be identified.

Concept introduction:

This is a chlorination reaction, and the electrophile is effectively the ${\text{Cl}}^{\text{+}}$ cation. The electrophilic aromatic substitution mechanism is performed for ortho, meta, and para substitution products. ${\text{OCH}}_{\text{3}}$ is an ortho/para director because the $\text{O}$-atom that attaches it to the ring has a lone pair of electrons, so the major products will be ortho and para isomers.

Interpretation Introduction

(b)

Interpretation:

The mechanism that leads to the ortho-, meta-, and para-disubstituted products for given reaction is to be drawn and major products are to be identified.

Concept introduction:

This is a Friedal Crafts alkylation reaction and $\text{CH}\text{C}{\text{H}}_{\text{2}}{}^{\text{+}}$ cation is the effective electrophile. The electrophilic aromatic substitution mechanism is performed for ortho, meta, and para substitution products. $\text{SC}\left(\text{O}\right){\text{CH}}_{\text{3}}$ is an ortho/para director because the $\text{S}$ atom that attaches it to the ring has a lone pair of electrons, so the major products will be ortho and para isomers.