AQA A Level Chemistry复习笔记7.8.1 Organic Synthesis

• It is possible to make a large number of organic products from a few starting compounds and the necessary 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
  • Halogenoalkanes
  • Alcohols
  • Carbonyls (aldehydes & ketones)
  • Carboxylic acids
  • Carboxylic acid derivatives
  • Amines
  • Nitriles
  • Arenes

   

Aliphatic Reaction Pathways

• The key functional groups and their interconversions are summarised here:

The diagram shows the main reaction pathways in aliphatic chemistry

Aliphatic Reactions Table

Aromatic Reaction Pathways

• The key aromatic reactions are summarised here:

Some of the key reaction pathways in aromatic chemistry

Aromatic Reactions Table

Choosing A Reaction Pathway

• Chemists will often have several choices of reaching a target molecule and those choices need to take into the principles of green chemistry

The twelve principles of green chemistry

• By choosing a pathway that has fewer steps, you can prevent waste and reduce energy demands which is better for the environment
  • This also reduces production costs

   

• By analysing the atom economy of each step, you can select reactions that give a higher atom economy
• Choosing alternative safer solvents also follows the principles of green chemistry

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

   

Answer 1

Answer 2