Allenes in Novel Palladium-Catalyzed and Acid-Mediated Cyclization Processes

The unique location of two orthogonal carbon carbon double bonds in the aliene moiety makes this functional group suitable for consecutive (tandem) reactions and the rapid build-up of molecular complexity.1 An addition reaction to one double bond usually leads either to an allylic or a vinylic functional group, or to both, which in several cases leads to enhanced reactivity of the molecule for further processes.