Recent applications of Cinchona alkaloid-based catalysts in asymmetric addition reactions

This review documents recently developed asymmetric addition reactions catalyzed by natural Cinchona alkaloids and their derivatives. These reactions include direct nucleophilic additions across the carbon–oxygen double bond and the carbon–nitrogen double bond, 1,4-additions, and cycloadditions. Natural and modified Cinchona alkaloids with different functionalities, such as amino, alkoxy, hydroxyl, amido, urea, and thiourea, especially on position C9, have been employed as catalysts in these reactions. Mechanistic considerations are discussed in many cases. In some cases, the application of adducts in further synthesis is also described.