In This Chapter
Seeing electrophilic aromatic substitution reactions of aromatics
Working through the synthesis of polysubstituted benzenes
Seeing nucleophilic aromatic substitution reactions
In Chapter 15, I discuss how you can determine whether a ring system is aromatic and what makes such aromatic compounds so stable. In this chapter, I show you how you can get such aromatic compounds to react by introducing a much hotter set of reagents than those used to react normal alkenes. These aromatic reactions are used to introduce multistep synthesis problems, or problems that require you to synthesize a complex structure by stringing together a sequence of known reactions.
Unlike the double bonds of alkenes, the double bonds in benzene are only weakly nucleophilic (nucleus loving), so you need powerful electrophiles (electron lovers) to make benzene react. You usually have to throw a full positive charge on the electrophile to make it strong enough to react with benzene. For example, Br2 reacts with alkenes but does not react with benzene. However, positively charged ...