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Reactions of Aromatic Compounds (overall)

Exercises: Friedel-Crafts Alkylation

Instruction : Exercise 1

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Fig.1

Exercise

A well-known method of introducing carbon side chains into aromatic compounds is known as the ...

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... Knoevenagel condensation.

... Meerwein rearrangement.

... Friedel-Crafts alkylation.

... Claisen rearrangement.

... Claisen alkylation.

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Exercise

In Friedel-Crafts alkylation, the carbon side chain that ought to be introduced into the aromatic compound is applied as an alykl halide whose halogen-carrying carbon is already positively polarized and, thus, electrophilic. Apart from the aromatic compound, what is, in addition, required for Friedel-Crafts alkylation?

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Nothing else. A stronger polarization of the reagent's carbon-halogen bond is not required.

Catalysis by a Lewis acid, which additionally polarizes the carbon-halogen bond and, thus, increases the carbon's electrophilicity.

The absence of any catalytically active contamination.

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Exercise

The strength of the polarization of the activated complex depends on the alkyl residue as well as on the ...

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... Lewis acid.

... Levis base.

... Louis acid.

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Exercise

Instead of alkyl halides, alternatively, in Friedel-Crafts alkylation, ...

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... carboxylic acids may be applied as sources of alkyl groups.

... alcohols may be applied as sources of alkyl groups.

... alkenes may be applied as sources of alkyl groups.

... halobenzenes may be applied as sources of alkyl groups.

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Exercise

Friedel-Crafts alkylation ...

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... easily occurs with deactivated aromatic compounds. The reaction is promoted by electron-withdrawing first substituents.

... does not occur with deactivated aromatic compounds. The reaction is prevented by electron-withdrawing first substituents.

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Exercise

Friedel-Crafts alkylation usually cannot be utilized for the synthesis of aromatic compounds with ...

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... saturated alkyl side chains, as, due to isomerization, the reaction with saturated alkyl halides mainly yields cyclic, aliphatic compounds with branched (isomeric) alkyl side chains.

... branched alkyl side chains, as, due to isomerization, the reaction with branched alkyl halides exclusively yields aromatic compounds with linear (isomeric) alkyl side chains.

... linear alkyl side chains, as, due to isomerization, the reaction with linear alkyl halides mainly yields aromatic compounds with branched (isomeric) alkyl side chains.

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Exercise

Friedel-Crafts alkylation is ...

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... reversible. Therefore, Lewis acid-catalyzed dealkylation can also occur.

... irreversible. Therefore, Lewis acid-catalyzed dealkylation can also occur.

... reversible. Therefore, Lewis acid-catalyzed dealkylation cannot also occur.

... irreversible. Therefore, Lewis acid-catalyzed dealkylation cannot also occur.

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