Synthetic Routes (OCR A Level Chemistry A): Revision Note

Multi-Stage Organic Synthetic Routes

• A large number of organic products are made from a few starting compounds using appropriate reagents and conditions

• Knowing how organic functional groups are related to each other is key to the synthesis of a given molecule

• The main functional groups you need to know are

  • Alkanes

  • Alkenes

  • Haloalkanes

  • Nitriles

  • Amines

  • Alcohols

  • Carbonyls (aldehydes & ketones)

  • Hydroxynitriles

  • Carboxylic acids

  • Esters

  • Acyl chlorides

  • Primary and secondary amides

Aliphatic Reaction Pathways

• The key interconversions between functional groups are summarised here:

Aliphatic Reactions Table

Aromatic Reaction Pathways

• The key aromatic reactions are summarised here:

Aromatic Reactions Table

Designing a Reaction Pathway

• The given molecule is usually called the target molecule and chemists try to design a synthesis as efficiently as possible

• Designing a reaction pathway starts by drawing the structures of the target molecule and the starting molecule

• Determine if they have the same number of carbon atoms

  • If you need to lengthen the carbon chain you will need to put on a nitrile group by nucleophilic substitution

• Work out all the compounds that can be made from the starting molecule and all the molecules that can be made into the target molecule

  • Match the groups they have in common and work out the reagents and conditions needed