Quiz - Electrophilic Aromatic Substitution - 1 | Electrophilic Aromatic Substitution
Organic Chemistry 2 - Quiz - Electrophilic Aromatic Substitution - 1
What is the first step of the halogenation of benzene?
The first step of the halogenation of benzene involves the generation of an electrophilic halogen species, typically by reacting a halogen (such as chlorine or bromine) with a Lewis acid catalyst (such as iron or aluminum chloride). This forms a halonium ion, which acts as an electrophile and initiates the electrophilic aromatic substitution reaction with benzene.
During the nitration of benzene, what reagents are necessary for generating the nitronium ion?
Nitric acid and sulfuric acid react to produce the nitronium ion, the active electrophile in the nitration of benzene.
Which of the following reactions is not an electrophilic aromatic substitution?
Benzyne is generated by the dehalogenation of 2-bromofluorobenzene by magnesium.
When considering electrophilic substitution reactions, halides are described as:
Halides are deactivating groups and ortho/para directing. Please note, deactivating groups are generally meta directing
When considering electrophilic substitution reactions, methoxy substituent is described as:
D ⇒ Donor:
- NH2, OH (strongly activating)
- NHCOR, OR (moderately activating) ⇒ ex: methoxy substituent
- alkyl, aryl (weakly activating)
When considering electrophilic substitution reactions, nitro substituent is described as:
Nitro substituent: NO2
A ⇒ Acceptor:
- N+R3, NO2, CF3, CN, SO3H (strongly deactivating)
- COH, COR, COOH, COOR, CONH2 (moderately deactivating)
Which substituent is the strongest activator?
NH2 (strongly activating) > MeO (moderately activating) > Br (moderately deactivating) > NO2 (strongly deactivating)
What is the best strategy to do an alkylation of benzene without overalkylation?
What is the best synthetic strategy for alkylating bromobenzene in the ortho position?
Br substituent is ortho/para directing. Because of the sterics, the para product will be preferred over the ortho product. In order to alkylate bromobenzene in the ortho position, the para position must be locked. A sulfonation of the para positon could be a good strategy:
