Determining the Directing Effects of a Substituent

14 Does chlorination of chlorobenzene require the use of a Lewis acid Explain why or why not  

15 Predict and explain the regiochemical outcome for chlorination of bromobenzene. 

The previous sections focused on the directing effects of a few specific groups (methyl, methoxy, nitro, and halogens). In this section, we will learn how to predict the directing effects for any substituent. That skill will prove to be essential in subsequent sections that deal with synthesis. 

Both activators and deactivators can be classified as strong, moderate, and weak. Each of these categories is described below, followed by a summary chart of all six categories. As discussed in the preceding sections, the activators are ortho-para directors, while the deactivators, except for the halogens, are meta directors. 

Strong activators are characterized by the presence of a lone pair immediately adjacent to the aromatic ring. 

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Friedel-Crafts Alkylation Friedel-Crafts Acylation Activating Groups Deactivating Groups Halogens The Exception Determining the Directing Effects of a Substituent... 

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