Directing Groups Flashcards
What is disubstitution?
When many substituted aromatic compounds can undergo a second substitution.
What is an example of disubstitution regarding benzene?
Phenylamine reacts more readily with bromine to produce a multi-substituted product.
Why is nitrobenzene less reactive than benzene to from disubstitution?
Nitrobenzene reacts slowly with bromine, requiring both a halogen carrier catalyst and a high temperature. The benzene ring in nitrobenzene is less susceptible to electrophilic substitution itself than in benzene.
What does nitrobenzene and bromine produce?
Only one product of 3-bromonitrobenzene.
How does the -NH2 in phenylamine react more readily to produce a multi-substituted product with bromine?
Because the -NH2 group activates the ring as the aromatic ring reacts more readily with electrophiles.
How does the -NO2 in nitrobenzene react less readily to only produce one substituted product with benzene?
Because the -NO2 group deactivates the aromatic ring as the ring reacts less readily with electrophiles.
What is the -NH2 group said to be in terms of directing in substitution?
Positions 2- and 4- directing in the second substituent.
What is the -NO2 group said to be in terms of directing in substitution?
Position 3 directing in the second substituent.
What are the activating groups?
All 2- and 4- directing groups (ortho and para-directors) with the exception of halogens.
What are the deactivating groups?
All 3-directing groups (meta directors).
How can using directing groups be used in organic chemistry?
When planning an organic synthesis.
How are directing groups on substituent groups used to plan organic sysnthesis? (4)?
- Identify the type of substitution.
- Identify the directing effect of the two substituents.
- Write out the two steps with the reagents needed for the synthesis.
- Is there a mixture of organic products to separate?
