Diels Alder Reaction
Contents
• Cycloaddition reaction
• Diel’s Alder reaction
Learning
Objectives
At the end of this
lecture, student will be able to
• Explain the concept involved in Diel’s Alder reaction
• Explain Cyclo addition reaction
Carbenes
• Definition
– Carbon with lone pair of electrons
– Highly reactive
• Examples
– Methylene, dichloro carbene
• Generation
Cycloaddition
Reaction
• Addition of carbene to alkene – cycloaddition
Types of
cycloaddition reactions
• [2+2] cycloaddition
• [4+2] cycloaddition
[2+2] cycloaddition
• Example
[4+2] cycloaddition or Diels – Alder reaction
– 1,4 – addition reaction
– Conjugated diene and dienophile
• Example
• Mechanism
• Reactivity of dienophile increased with electron
withdrawing group
• Examples
Summary
• Carbenes –
divalent carbon compounds – highly unstable
• Cycloaddition
reactions – carbenes add to alkenes to generate cyclic ring
• Types of
cycloaddition reactions – [4+2] cycloaddition and [2+2] cycloaddition
• Diel’s Alder reaction
– [4+2] cycloaddition reaction – involves reaction between conjugated
dienes and dienophile