The Cope rearrangement is a chemical reaction that involves the rearrangement of certain types of organic compounds called 1,5-hexadienes. In this process, the diene undergoes a thermal isomerization, resulting in the formation of new isomers. This reaction typically occurs at elevated temperatures and does not require any catalysts. During the Cope rearrangement, the molecular structure changes through a concerted mechanism, meaning that bonds are broken and formed simultaneously. The reaction is significant in organic chemistry because it allows for the synthesis of various compounds with different properties, making it useful in the development of pharmaceuticals and other chemical products.