Claisen rearrangement over the past nine decades

The Claisen rearrangement offers a potentially useful synthetic tool to the organic chemist. A general overview is given covering the most relevant topics related to the Claisen rearrangement, starting from its first publication in 1912 as a new reorganization of allyl aryl (or vinyl) ethers up to its most recent applications in different organic chemistry fields. First, the enzymatic version of the Claisen rearrangement is described. Second, the study of the stereoselective version of the rearrangement is discussed. Finally, applications of the reaction are presented, including, the preparation of a wide range of synthetically interesting building blocks and natural or biologically active compounds.