Quiz - Benzene Derivatives | Electrophilic Substitution of Benzene Derivatives
Which of the following reactions is not an electrophilic aromatic substitution?
The formation of nitrobenzene
The formation of benzene sulfonic acid
The formation of benzyne
The formation of bromobenzene
Benzyne is generated by the dehalogenation of 2-bromofluorobenzene by magnesium
When considering electrophilic substitution reactions, halides are described as:
Ortho/para directing and activating
Ortho/para directing and deactivating
Meta directing and activating
Meta directing and deactivating
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:
Ortho/para directing and activating
Ortho/para directing and deactivating
Meta directing and activating
Meta directing and deactivating
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:
Ortho/para directing and activating
Ortho/para directing and deactivating
Meta directing and activating
Meta directing and deactivating
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?
MeO
Br
NH2
NO2
NH2 (strongly activating) > MeO (moderately activating) > Br (moderately deactivating) > NO2 (strongly deactivating)
What is the best synthetic strategy for alkylating bromobenzene in the ortho position?
Friedel-Crafts Acylation followed by a reduction
Sulfonation, Friedel-Crafts Alkylation, Desulfonation
Substitution Nucleophile with halogenoalkane
Friedel-Crafts Alkylation followed by an elimination
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:
