Ipso Substitution
Ipso substitution a special case of electrophilic aromatic substitution where the leaving group is not hydrogen.
A classic example is the reaction of salicylic acid with a mixture of nitric and sulfuric acid to form picric acid. The nitration of the 2 position involves the loss of CO2 as the leaving group.
Desulfonation in which a sulfonyl group is substituted by a proton is a common example. See also Hayashi rearrangement.
In aromatics substituted by silicon, the silicon reacts by ipso substitution.
Read more about this topic: Electrophilic Aromatic Substitution
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