Asymmetric organocatalytic cyclization and cycloaddition reactions

Asymmetric organocatalysis has been providing powerful and practical methods for the highly stereo-controlled construction of a huge variety of carbo- and heterocyclic compounds. In the case of polycyclic systems, either fused, bridged, or spiranic ring arrangements can be accessed. Around 150 different small chiral organic molecules have been proven to be useful catalysts in asymmetric cyclization, annulation, and cycloaddition processes. Some of these processes such as ntramolecular aldol reactions, intramolecular aza-Michael reactions, or Diels-Alder cycloadditions, have reached impressive levels of stereoselective control and are increasingly being used in enantioselective total syntheses. Polyene cyclizations, domino processes, combination of organocatalysis with transition metal-based catalysis and/or biocatalysis, polymer-supported and supramolecular-gel-supported catalysts, self-assembled organocatalysts, and multiphase homogeneous catalysis and flow chemistry are experiencing a fast growth.