Organic Test 5 Flashcards
What is the polygon rule?
You can form a polygon with a conjugated ring to determine stability and number of bonding, nonbonding, and antibonding electrons
What is the mechanism for the formation of a stronger electrophile in the bromination of benzene?
What is the name of this functional group?
acetophenone
Name? position?
o-dichlorobenzene
1,2-dichlorobenzene
(ortho)
The sulfonation reaction is reversible by using either concentrated/dilute sulfuric acid. Which is which?
What is the name of this group?
acetyl
What kind of directors are anisole groups?
STRONG activators, so they are:
ortho para directors.
They ortho and para positions are stabilized by resonance
What kind of directors are alkyl groups?
They are activators, so they are:
ortho-para directors
What are all of the ortho-para, activator groups?
Aka alkylbenzenes and groups with lone pairs to stabilize resonance forms.
What kind of director are halogens?
They are deactivating BUT ortho-para directors
What is the difference between the phenyl and benzyl groups?
What is the name of this functional group?
benzaldehyde
If two groups donate, what is more important, resonance or induction?
Resonance is more important.
Fyi, CH3 donates by induction
Cl donates by resonance
Name?
benzoic acid
Name?
anisole
(methoxybenzene)
What kind of directors are ketones and aldehydes?
meta-directors, deactivators
What kind of director is sulfonic acid?
Meta-director, deactivator
When both meta directors and O/P directors are present, which wins?
O/P
In Birch reduction of substituted benzenes, how do we know where the 1,4 diene goes?
deactivators: are reduced
activators: are NOT reduced
What kind of directors are esters?
Meta-directors, deactivators
name?
styrene
(vinylbenzene)
What are 2 limitations of the friedel-crafts reaction?
- Friedel-crafts reactions work only with benzene, activated benzene derivatives, and halobenzenes.
Does not work with:
- deactivating group stronger than a halogen (NO2, SO3H, CO2H, CN, R-C=O, H-C=O, +NR3, -O-R-C=O)
- Lewis acid-base adduct formed from amino groupsm (NH2, NHR, NR2)
2. susceptible to carbocation rearrangement, therefore you can’t make straight chain alkanes.
What kind of director is the nitro group?
Deactivator,
Meta-director
What kind of director is the cyano group?
meta-director, deactivator
What kind of directors are aniline groups?
Aniline groups are activators
they are ortho para directors due to resonance stabilized ortho and para positions.
What is necessary for compounds to be aromatic?
- The structure must be cyclic and contain conjugated pi bonds
- Each atom must have an unhybridized p orbital (sp2 or sp)
- The unhybridized p orbitals must overlap to form a continuous ring of parallel orbitals. Must be planar for effective overlap
what is the name of this group?
acyl group
What kind of director is quartenary ammonium?
Meta-director, deactivator
Name?
toluene
(methylbenzene)
Name?
aniline
(benzenamine)
What is the preliminary step to form the strong electrophile needed in the nitration of benzene?
name?
phenol
(benzenol)
What is the connection between the number of conjugated double bonds and UV absorption?
A compound that has a longer chain of conjugated double bonds, absorbs UV at a HIGHER wavelength
Name? Position?
p-nitrophenol
IUPAC: 4-nitrophenol
(para)
Name?
acetophenone
(methyl phenyl ketone)
Name?
benzaldehyde
What is the best way to add an amino group to an aromatic ring?
Starting with a nitro group is the best way to get an amino group with a metal catalyst.
What is the mechanism for electrophilic aromatic substitution?
If a conjugated system meets the three rules of aromaticity, how do you determine if it is aromatic or antiaromatic?
aromatic: 4N+2 rule
antiaromatic: 4N rule
where n is the number of pi electrons
What is the name of this functional group?
anisole
Name? Position?
m-chloroperoxybenzoic acid
IUPAC: 3-chloroperoxybenzoic acid
(meta)
