Aromatic Compounds

Question 1

What is the criteria for aromatic compounds?

Answer 1

1. Structure must be cyclic, containing some number of conjugated pi bonds
2. Each atom in the ring must have an unhybridized p orbital. Usually sp2 or
   occasionally sp hybridised
3. Unhybridized p orbitals must overlap to form a continuous ring of parallel
   orbitals (conjugated). Structure must be planar (or nearly planar) for effective
   overlap to occur
4. Delocalisation of the pi electrons over the ring must lower the electronic
   energy

Question 2

What are antiaromatic compounds❔

Answer 2

Antiaromatic compound: meets the first three criteria, but delocalisation of
the pi electrons over the ring increases the electronic energy
Aromatic, Antiaromatic, and Nonaromatic Compounds
more stable (aromatic)less stable
Aromatic structures are more stable than their open-chain counterparts

Question 3

What are non aromatic compounds?

Answer 3

cyclic compound that does not have a continuous, overlapping ring of p orbitals. Its electronic energy is similar to that of its open-chain counterpart

Question 4

What is huckles rule?

Answer 4

Aromatic or antiaromatic: a cyclic compound must have a continuous ring of
overlapping p orbitals, usually in a planar conformation.

Question 5

How many pi electrons in aromatic vs anti aromatic?

Answer 5

aromatic = 6
anti aromatic = 4

Question 6

What are the 6 aromatic compound reactions?

Answer 6

1. Electrophilic aromatic substitution
2. Nucleophilic aromatic substitution
3. Organometallic Couplings
4. Addition reactions
5. Side-chain
   reactions
6. Oxidation of phenols to quinones

Question 7

What are the combinations for couplings using lithium dialkylcuprate reagents (Gilman reagents)?

Answer 7

An aryl halide with an alkyl or vinyl cuprate
A vinyl halide with an aryl cuprate
An alkyl halide with an aryl cuprate.
An acyl halide with an organocuprate
giving a ketone

Question 8

What is the heck reaction?

Answer 8

Coupling of an aryl or vinyl halide with an alkene to give a new C-C bond at
the less substituted end of the alkene, usually with trans stereochemistry

Question 9

What is the Suzuki reaction?

Answer 9

Palladium-catalysed substitution that couples an aryl or vinyl halide with an
alkyl, alkenyl, or aryl boronic acid or boronate ester

Question 10

What are the different reactions of phenol?

Answer 10

• fisher esterification
• Williamson ether synthesis
• oxidation to quinones