Resonance arenediazonium salts

Arenediazonium salt A derivative of the resonance-stabilized benzenediazoni-um cation, C6H5N2 . 

Arenediazonium salt A derivative of the resonance-stabilized benzenediazonium cation, C6H5N2 +. Aromatic compound (1) Benzene or a derivative—represented by a structure with three double bonds in... 

As mentioned in Section 22-4, V-nitrosation of primary benzenamines (anilines) furnishes arenediazonium salts, which can be used in the synthesis of phenols. Arenediazonium salts are stabilized by resonance of the tt electrons in the diazo function with those of the aromatic ring. They are converted into haloarenes, arenecarbonitriles, and other aromatic derivatives through replacement of nitrogen by the appropriate nucleophile. 

The reason for the stability of arenediazonium salts, relative to their alkane counterparts, is resonance and the high energy of the aryl cations formed by loss of nitrogen. One of the electron pairs making up the aromatic rr system can be delocalized into the functional group, which results in charge-separated resonance structures containing a double bond between... 

In Summary Arenediazonium salts, which are more stable than alkanediazonium salts because of resonance, are starting materials not only for phenols, but also for haloarenes, arenecarbonitriles, and reduced aromatics by displacement of nitrogen gas. The intermediates in some of these reactions may be aryl cations, highly reactive because of the absence of any electronically stabilizing features, but other, more complicated mechanisms may be followed. The ability to transform arenediazonium salts in this way gives considerable scope to the regioselective construction of substituted benzenes. 

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