Return to Contents Chapter 10: Conjugation in Alkadienes and Allylic Systems Ch 10 contents

Resonance

Resonance is probably one of the most important concepts that one needs to master in order to understand organic chemistry, yet it is often under appreciated or misunderstood and misused.  We first met resonance in Ch 1 (review)

Things to remember about resonance :

allyl cation resonance Resonance stabilisation of a cation
allyl anion resonance Resonance stabilisation of an anion
systems where resonance will be important
  1. allyl chloride : very reactive in nucleophilic substitution reactions
  2. 1,3-butadiene : can undergo addition via two different modes
  3. propenal : nucleophiles can add to the C=C due to the presence of the conjugated C=O (see Chapter 18)

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Dr. Ian Hunt, Department of Chemistry, University of Calgary