Cope rearrangement: Mechanism and examples

Table of Contents

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

References:

  • Wang, Z., Comprehensive Organic Name Reactions and Reagents, John Wiley & Sons, Inc.,2010
  • 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.

Cope rearrangement

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