Constitutional Dynamics Generation of Dynamic Constitutional Diversity and Driven Evolution in Helical Molecular Strands under Lewis Acid Catalyzed Component Exchange** Nicolas Giuseppone, Jean-Louis Schmitt, and Jean-Marie Lehn* Constitutional dynamic chemistry (CDC) [1] rests on the implementation of dynamic features that act on the consti- tution of molecular [2] as well as supramolecular [3] entities [*] Dr. N. Giuseppone, J.-L. Schmitt, Prof. Dr. J.-M. Lehn Institut de Science et d’IngØnierie SupramolØculaires 8 AllØe Gaspard-Monge, BP 70028 67083 Strasbourg cedex (France) Fax: (+ 33)3-9024-5140 E-mail: lehn@isis.u-strasbg.fr [**] This work was supported by a predoctoral fellowship from the Ministre de la Jeunesse, de la Recherche et de la Technologie (J.-L.S.). Communications 4902 # 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/anie.200460343 Angew. Chem. Int. Ed. 2004, 43, 4902 –4906