Cope rearrangement definition

Oxy-, Anionic Oxy-, Dianionic Oxy-, Hetero-)Cope Rearrangements 1.6.3.1.2.1. General Aspects Introduction and Definitions... 

In the Cope rearrangements of terminal substituted substrates, new stereogenic centers are created at positions 1 or 6. The configuration of these stereocenters is often regulated by a stereocenter which is immediately attached to the new one or by a remote stereocenter. This section discusses stereochemical aspects which concern relative asymmetric induction in Cope rearrangements. For the definition of the term relative asymmetric induction see also Section 1.6.3.1.1.5. p 3481. 

Ultimately, these experimental studies cannot completely rule out biradical intermediates in the Cope rearrangement, especially for the heavily substituted systems. In the end, only theory can make a definitive statement about the structure of a transition state. The interplay between theory and experiment in the Cope rearrangement and other pericyclic processes has at times been contentious. In addition, differing theoretical models have often made diametrically opposed predictions (see the Going Deeper highlight on page 900). This further fueled the debate over the true nature of pericyclic transition states. 

Figure 4 Definitions of geometrical parameters for the transition state of (a) Cope rearrangement (b) Claisen rearrangement...

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