What are the limitations of Foucault alkylation reaction?

① Due to the extremely unstable carbocation formed by aryl and vinyl halides, it cannot be used for this reaction.

② The presence of passivation groups on the aromatic ring, such as NH2 groups, can lead to the deactivation of the catalyst due to the formation of complex compounds.

③ Excessive aromatic compounds must be used in these reactions to avoid polyalkylation (adding more than one alkyl group to the aromatic compound).

④ Aromatic compounds with lower activity than monohalobenzenes do not participate in the Friedel-Crafts alkylation reaction.