Greener Approaches to Selected Asymmetric Addition Reactions Relevant to Drug Development

Asymmetric organic synthesis is of paramount importance in the development of drugs. Asymmetric addition reactions such as aldol reaction, Michael addition, and Mannich addition reactions are important carbon-carbon bond-forming reactions and have been employed in the synthesis of a broad range of biologically important molecules. Many of these reactions have been developed under solvent-free conditions or in greener solvents like water. Several reactions have been developed at room temperature or by using a non-conventional energy source such as microwave irradiation. Several greener catalysts have been developed for such reactions. The present review article discusses the application of green chemistry parameters in the development of selected asymmetric addition reactions leading to biologically important molecules during the last ten years. Asymmetric aldol reactions, asymmetric Michael reactions, and different asymmetric addition reactions involving imines such as Mannich reaction, aza-benzoin reaction, etc. in aqueous media or under solvent-free conditions have been reviewed. Application of different types of catalysts such as prolinamides, 1,2-diamines, polymer and magnetic nanoparticle-supported chiral catalysts is demonstrated.