Cope rearrangement

The Cope rearrangement is a reaction from the field of organic chemistry and goes to the American chemist Arthur C. Cope - back (1908, 1966). It represents a thermally induced [3,3 ] - sigmatropic shift, and one of the pericyclic reactions. In Fig.1 it is illustrated by the example of a substituted 1,5 - hexadiene. The biallylische bond between carbon 3 and 4 is relatively weak and can be easily split. The Cope rearrangement of unsubstituted 1,5-hexadiene, 1,5-hexadiene supplies; This is an unusual example of a reaction which is the same for the starting material and product. The reaction sequence was confirmed via labeling experiments.

The Cope rearrangement can run both a chair-shaped, as well as a well-shaped transition state. Both of these conformations are shown in Figure 3 an example of the cyclohexane. In most cases, the chair conformation is strongly preferred. Of the two possible chair conformations that it is preferable to take in more or larger substituents equatorial positions.