Cope rearrangement: Mechanism and examples

Cope rearrangement reaction, examples, mechanism, and its variations along with stereochemistry have been discussed here. Cope rearrangement is quite similar to claisen rearrangement, both are [3,3] sigmatropic rearrangement reactions.

Cope rearrangement reaction

Cope rearrangement is a thermal isomerization of a 1,5-diene through [3,3]-sigmatropic rearrangement giving a more stable 1,5-diene as a product. Let’s see an example of a cope rearrangement reaction.

cope rearrangement
Cope rearrangement

Various types of cope rearrangement reactions have been reported such as oxy-cope rearrangement, aza-cope rearrangement, anionic oxy cope rearrangement reaction, etc.

Some properties of Cope rearrangements are given as:

  • These reactions can be induced thermally or photochemically.
  • These reactions proceeds via the concerted mechanisms.
  • Reactions takes place in solution as well as in vapour phases.

cope rearrangement mechanism

The mechanism of cope rearrangement involves a concerted mechanism as represented below:

cope rearrangement mechanism
Mechanism of cope rearrangement

oxy cope rearrangement

When a hydroxyl group is present at position-3 of the 1,5-diene, the rate of rearrangement is increased rapidly when treated with a strong base like potassium hydride (KH). Such a reaction is called oxy-cope rearrangement.

oxy cope rearrangement
oxy-cope rearrangement

aza cope rearrangement

Let’s see an example of aza cope rearrangement.

aza cope rearrangement

aza cope rearrangement mechanism

The mechanism of aza cope rearrangement is shown below:

aza cope rearrangement mechanism

Anionic oxy cope rearrangement

An example of oxy cope rearrangement is given below with its mechanism.

anionic oxy cope rearrangement
Anionic oxy-cope rearrangement

Cope Rearrangement Video

Cope Rearrangement reaction


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  • J.J. Li, Name Reactions, 4th ed.,© Springer-Verlag Berlin Heidelberg 2009
  • Skyes, P., A Guide Book to Mechanism in Organic Chemistry, Second edition, Orient Longman Ltd., 1988
  • March, J., Advanced Organic Chemistry, Wiley Eastern Limited, 1986.
  • Morrison, R. T., & Boyd, R. N., Organic chemistry, Allyn and Bacon, Inc. 1987

If you have any problems related to this topic, please comment without hesitation. Thank you.

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