Aromatic Substitution of Anilines via Diazonium Salts

Problem 3.12. In the Stiles reaction, the highly reactive compound benzyne is obtained by treatment of anthranilic acid (2-aminobenzoic acid) with NaN02 and HCl. Draw a mechanism for this reaction. 

The aryldiazonium ion is usually prepared in situ and then immediately combined with a nucleophile to give a substitution product. The mechanisms of the substitution reactions vary greatly with the nucleophile, ranging all across the mechanistic spectrum of organic chemistry. For example, both hypophosphorous acid (H3P02) and I react with diazonium ions by an SrnI mechanism (Chapter 2) to give the reduced arenes or aryl iodides, respectively. 

The nucleophiles H20 and BF4- react with aryldiazonium ions to give phenols and aryl fluorides, respectively. Because neither H2O nor BF4 are oxidiz-able enough to transfer an electron to the aryldiazonium ion, only SN1 mechanisms are reasonable for these reactions. 

Finally, the terminal N of aryldiazonium ions is also electrophilic, and electron-rich aromatic compounds such as phenols and anilines undergo electrophilic 

Problem 3.12. Draw reasonable mechanisms for the following reactions  

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