Benzene and other aromatic hydrocarbons usually have such strikingly different properties from typical open-chain conjugated polyenes, such as 1,3,5-hexatriene, that it is convenient to consider them ...Benzene and other aromatic hydrocarbons usually have such strikingly different properties from typical open-chain conjugated polyenes, such as 1,3,5-hexatriene, that it is convenient to consider them as a separate class of compounds called arenes. In this chapter we shall outline the essential features of the chemistry of arenes, particularly their reactions with electrophilic reagents which result in the substitution of a ring hydrogen with other functional groups
