• Hydrocarbons — carbon and hydrogen only
  • Alkanes (single bonds)
  • Alkenes (one or more C=C)
  • Alkynes (one or more C≡C)
  • Arenes (aromatic rings)
• Halogen-containing
  • Alkyl halides
• Oxygen-containing
  • Alcohols and phenols (C–OH)
  • Ethers (C–O–C)
  • Carbonyl-containing groups (C=O)
    • Aldehydes and ketones (simple carbonyls — undergo addition)
    • Carboxylic acid derivatives (carbonyl + heteroatom leaving group — undergo substitution)
      • Carboxylic acids
      • Acid chlorides
      • Anhydrides
      • Esters
      • Amides
    • Acetals and hemiacetals (carbonyl + alcohol addition products)
• Nitrogen-containing
  • Amines
  • Amides (also a carbonyl-containing group, above)
• Aromatic heterocycles — bridge the aromatic and heteroatom families

The single most useful split in this tree is between the simple carbonyls (aldehydes, ketones — no good leaving group, so they undergo addition) and the acyl derivatives (carboxylic acids and their relatives — a heteroatom leaving group is present, so they undergo substitution). This distinction, developed in Chapters 12 and 13, explains most of carbonyl chemistry.

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