Benzene, chlorination from cumene

The Friedel—Crafts alkjiation reaction is an electrophilic aromatic substitution that attaches an alkyl group to the aromatic ring. It is named for Charles Friedel (1832-1899) and James M. Crafts (1839—1917), who discovered it by acddent when they tried to synthesize pentyl chloride from pentyl iodide through reaction with aluminum chloride in an aromatic solvent. Instead of the hoped-for chloride, substituted aromatic hydrocarbons appeared. The Friedel-Crafts reaction is closely related to bromination and chlorination of benzene. If we treat benzene with isopropyl bromide in the hope that a nucleophilic attack of benzene on isopropyl bromide will produce isopropylbenzene (cumene), we are sure to be disappointed (Fig. 14.34). Benzene is by no means a strong nucleophile and isopropyl bromide can scarcely be described as a powerful electrophile. The proposed reaction is utterly hopeless, and ftuls to give product. 

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