Organic Chemistry Reviews Chapter 14

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Organic Chemistry ReviewsChapter 14

• Cindy Boulton
• March 22, 2009

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Aromatic Compounds

• Benzene
• 6 member ring
• 6 p electrons
• Alternating Double Bonds
• Resonance Hybrid
• All bonds 1 ½ - same length
• Only as many Hydrogen Atoms as Carbon Atoms

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Nomenclature of Benzene Derivatives

• Disubstituted Benzene
• Ortho 1,2
• Meta 1,3
• Para 1,4
• Phenyl
• group name of a benzene attached to a parent
  chain
• Toluene
• Benzene with one methyl group attached
• Xylene
• Benzene with two methyl groups attached
• Ortho, meta, or para
• Phenol
• Benzene with a hydroxyl group attached (-OH)
• Alcohol

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Nomenclature of Benzene Derivatives

• Aniline
• Benzene with a amine group attached (-NH2)
• Anisole
• Benzene with an ether bond to a methyl group
• Phenly-O-Methyl
• Acetophenone
• Benzene with an acetyl group attached
• Phenyl-(CO)-Methyl
• Benzaldehyde formyl group attached,
  Phenyl-(CO)-H
• Oil of bitter almond
• Benzophenone two benzene rings attached,
  Phenyl-(CO)-Phenyl

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Nomenclature of Benzene Derivatives

• Benzoic Acid
• Benzene with a carboxyl group attached,
  Phenyl-(CO)-OH
• Benzenesulfonic Acid
• Benzene with HSO3 attached
• Nitrobenzene
• Benzene with nitrite attached (-NO2)

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Stability of Benzene

• Stability of conjugate p systems
• Pseudo p bond is formed
• Some of the p electron density is delocalized
• The p bond is spread out and becomes harder to
  react
• More stable
• Stability of aromatic compounds
• Resonance stabilizaion
• Forms a resonance hybrid
• Delocalization of electrons by molecular orbitals
• The p bond electrons are completely delocalized

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Aromatic Compounds

• Aromatic Rules
• 1) Cyclic
• 2) Planar
• P-orbitals have to line up to from p bonds
• 3) A Huckle Number of Delocalizable electrons
• Huckle Number 6,10,14,18,
• All sp2 Carbons and alternating double bonds
• Annulene
• Benzene 6 annulene
• Benzoid Polycyclic aromatic
• 6-member rings fused together
• Non-Benzoid Polycyclic aromatic
• Non 6-member rings fused together (12)

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Heteroatomic Aromatics

• Not Carbon
• Follow Aromatic Rules
• Cyclic
• Planar
• Delocalizable electrons (Huckle Number)
• Lone pair
• Can be planar, perpendicular to ring, with other
  electrons to be counted as delocalizable
  electrons
• Can be non-planar, not perpendicular, and not
  delocalizable depending on geometry of molecule
• Pyridine, Furan, Pyrole, Thiophene

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Aromatic Compounds with Charge

• 5-Carbon ring
• 4 delocalizable electrons Electron pair 6
  delocalizable electrons
• Negative Charge
• 7-Carbon ring
• 6 delocalizable electrons vacant orbital 6
  delocalizable elcetrons
• Positive Charge