Advanced Organic Chemistry

8

Aromatic Substitution

LEARNING OBJECTIVES

By the end of this chapter you should be familiar with

• The mechanism of electrophilic aromatic substitution.
• How a variety of substituents can be substituted into the benzene ring.
• The effects of substituents on orientation and reactivity, activation and deactivation.
• The mechanism of nucleophilic substitution in aromatic systems.

8.1 INTRODUCTION

Substitution reactions at an aliphatic carbon are generally nucleophilic. In aromatic systems the situation is reversed. Three types of reagents can perform substitution in aromatic compounds, that is, electrophiles, nucleophiles and free radicals. In this chapter, we will deal with electrophilic and nucleophilic substitutions; the substitution brought about ...