The key difference between Cope and Claisen rearrangement is that the reactant of Cope rearrangement is a 1,5-diene whereas the reactant of Claisen rearrangement is an allyl vinyl ether.
Both Cope rearrangement and Claisen rearrangement are types of rearrangement reactions involved in the [3,3]-sigmatropic rearrangements. The Cope rearrangement was named after Arthur C. Cope while Claisen rearrangement was named after Rainer Ludwig Claisen. There are many variations of both these rearrangement types. There are some variations of Cope rearrangements which include the Aza-Cope rearrangements, Claisen rearrangement, etc. Some variations of Claisen rearrangements include aromatic Claisen rearrangement, bellus-Claisen rearrangement, Ireland-Claisen rearrangement, etc.
CONTENTS
1. Overview and Key Difference
2. What is Cope Rearrangement
3. What is Claisen Rearrangement
4. Side by Side Comparison – Cope vs Claisen Rearrangement in Tabular Form
5. Summary
What is Cope Rearrangement?
Cope rearrangement is a type of rearrangement reaction in which a 1,5-diene undergoes [3,3]-sigmatropic rearrangements. The reaction was named after Arthur C. Cope, who developed a mechanism for this reaction. This type of reaction is very important in organic synthesis reactions. There is a transition state for this reaction. This transition state passes through a boat-like or a chair-like structure. eg., expansion of cyclobutane ring into a 1,5-cyclooctadiene ring. That is to form the two cis double bonds. The reaction is as follows:
There are some variations of Cope rearrangements which include Aza-Cope rearrangements, Claisen rearrangement, etc.
What is Claisen Rearrangement?
Claisen rearrangement is a type of rearrangement reaction in which allyl vinyl ethers convert into γ,δ-unsaturated carbonyl compounds. Moreover, it is named after Rainer Ludwig Claisen, who discovered this reaction in 1912. The rearrangement occurs through [3,3]-sigmatropic rearrangements.
This reaction is an exothermic reaction which includes bond cleavage and recombination. It is a stereospecific reaction. It has the first-order kinetics. The transition state of Claisen rearrangement is a highly ordered cyclic structure. Moreover, there are solvent effects which affect the reaction progression. i.e. polar solvents accelerate the reaction. There are some variations of Claisen rearrangements which include aromatic Claisen rearrangement, Bellus-Claisen rearrangement, Ireland-Claisen rearrangement, Johnson–Claisen rearrangement, Photo-Claisen rearrangement, etc.
What is the Difference Between Cope and Claisen Rearrangement?
Both Cope rearrangement and Claisen rearrangement are types of rearrangement reactions involved in the [3,3]-sigmatropic rearrangements. The key difference between Cope and Claisen rearrangement is that the reactant of Cope rearrangement is a 1,5-diene whereas the reactant of Claisen rearrangement is an allyl vinyl ether. Furthermore, the product of Cope rearrangement is a different diene while the produce of Claisen rearrangement is γ,δ-unsaturated carbonyl compounds. So, this is another difference between Cope and Claisen rearrangement.
Moreover, the Cope rearrangement was named after Arthur C. Cope while Claisen rearrangement was named after Rainer Ludwig Claisen. There are some variations of Cope rearrangements which include the Aza-Cope rearrangements, Claisen rearrangement, etc. There are some variations of Claisen rearrangements which include aromatic Claisen rearrangement, Bellus-Claisen rearrangement, Ireland-Claisen rearrangement, Johnson–Claisen rearrangement, Photo-Claisen rearrangement, etc.
Summary – Cope vs Claisen Rearrangement
Both Cope rearrangement and Claisen rearrangement are types of rearrangement reactions involved in the [3,3]-sigmatropic rearrangements. The key difference between Cope and Claisen rearrangement is that the reactant of Cope rearrangement is a 1,5-diene whereas the reactant of Claisen rearrangement is an allyl vinyl ether. Moreover, the product of Cope rearrangement is a different diene while the produce of Claisen rearrangement is γ,δ-unsaturated carbonyl compounds.
Reference:
1. “Cope Rearrangement.” Chemistry LibreTexts, Libretexts, 3 June 2019, Available here.
2. “Claisen Rearrangement.” Wikipedia, Wikimedia Foundation, 16 Sept. 2019, Available here.
3. “Cope Rearrangement.” Wikipedia, Wikimedia Foundation, 24 Oct. 2019, Available here.
Image Courtesy:
1. “Cope Rearrangement Scheme” (CC BY-SA 3.0) via Commons Wikimedia
2. “Claisen Rearrangement Scheme” By ~K – Own work (CC BY-SA 3.0) via Commons Wikimedia