Calix[ n ]arenes in Action: Recent Applications in Organocatalysis

The use of calix[ n ]arenes as organocatalysts has increasingly been considered a prime focus due to their adjustable three‐dimensional molecular structure, easy synthesis, and versatile structural modification at the upper and lower edges. For instance, these macromolecules have been described as efficient catalysts for asymmetric aldol reactions, asymmetric Michael addition, esterification and transesterification, dehydration, nucleophilic aromatic substitution, and multicomponent reactions. Furthermore, calix[ n ]arenes also tolerate aqueous or solvent‐free reaction systems and can be supported on solid and/or magnetic particles, showing cost, time and energy savings, easier experimental procedures, and chemical waste reduction.