19. Reactions of Aromatics: EAS and Beyond

Are the following substituents ortho–para directors or meta directors?

a. CH=CHC≡N 

b. NO₂ 

c. CH₂OH

Predict the major productof the following EAS reaction.

Predict the product of the following multi-step synthesis.

p-Xylene undergoes nitration much faster than benzene. Use resonance forms of the sigma complex to explain this accelerated rate

For each horizontal row of substituted benzenes, indicate

a. the one that is the most reactive in an electrophilic aromatic substitution reaction.

List the compounds in each set from most reactive to least reactive toward electrophilic aromatic substitution:

b. dichloromethylbenzene, difluoromethylbenzene, toluene, chloromethylbenzene

List the compounds in each set from most reactive to least reactive toward electrophilic aromatic substitution:

a. benzene, phenol, toluene, nitrobenzene, bromobenzene

Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:

b. 1-chloro-2,4-dinitrobenzene, 2,4-dinitrophenol, 1-methyl-2,4-dinitrobenzene

Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:

e. p-methylnitrobenzene, 2-chloro-1-methyl-4-nitrobenzene, 1-methyl-2,4-dinitrobenzene, p-chloromethylbenzene

Rank each group of compounds from most reactive to least reactive toward electrophilic aromatic substitution:

f. bromobenzene, chlorobenzene, fluorobenzene, iodobenzene

For each horizontal row of substituted benzenes, indicate

c. the one that yields the highest percentage of meta product in an electrophilic aromatic substitution reaction.

Why is anisole nitrated more rapidly than thioanisole under the same conditions?

A mixture of 0.10 mol benzene and 0.10 mol p-xylene was allowed to react with 0.10 mol nitronium ion until all the nitronium ion was gone. Two products were obtained: 0.002 mol of one and 0.098 mol of the other.

b. Why was more of one product obtained than of the other?