Edexcel A Level Chemistry:复习笔记7.6.2 Planning Reaction Schemes

Planning Reaction Schemes


  • 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


Worked Example

Suggest how the following syntheses could be carried out:

a) Chloroethane to ethanoic acid

b) Ethene to 1-aminopropane

Answer 1



Answer 2



Exam Tip

You could be required to design a synthesis with up to four steps

Part of this process can include identifying appropriate control measures to reduce risk, based on data about hazards