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Limitations of Friedel-Crafts alkylation
4. FC reactions do not occur when the ring bears an NH2, NHR or NR2 groups
because amino groups become electron-withdrawing when they react with the
Lewis acid in the reaction.
Nitrogen forms a strong complex with the Lewis acid. This complex then withdraws
electrons from the ring, rather than donating electrons as the neutral nitrogen did.
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Limitations of Friedel-Crafts alkylation
5. Aryl and vinylic halides cannot be used in F.C. alkylation as they do not form
carbocations.
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