SUGAR-BASED ORGANOCATALYSTS AND CHIRAL SALEN COMPLEXES FOR ENANTIOSELECTIVE SYNTHESIS

Abstract

The thesis entitled "Sugar-based Organocatalysts and Chiral Salen Complexes for Enantio selective Synthesis" has been divided into five chapters. The title of the thesis reflects our objective observably, which includes the synthesis and characterization of various monosaccharide derivatives and their corresponding prolinamides and their applications as organocatalysts for the asymmetric synthesis of |3-hydroxy ketones and y-nitro ketones. Furthermore, we synthesized chiral Co(III) complexes and evaluated their catalytic activity for the enantioselective synthesis of biologically important vesicular acetyl choline transporter inhibitors. Chapter 1: Introduction This chapter details the brief review on the importance of organocatalysis as well as metal catalysis in asymmetric synthesis. Enantioselective synthesis has become one of the most significant aims in synthetic organic chemistry, agricultural chemistry, medicinal chemistry, natural products chemistry and pharmaceutical industry. The use of catalytic asymmetric approach for the synthesis ofchiral compounds is one ofthe most elegant and desirable methods in terms of atom economy and a progressively more important issue in organic chemistry. In catalytic approach, catalytic amount of chiral metallic or metal free organic molecules is employed in the reaction followed by the regeneration in parallel catalytic cycle for further use. Though the metal catalysts have significant advantages in asymmetric synthesis over the organic molecules such as molecular and structural diversity, a large number of reacting partners that can easily tuned by varying ligands, they offer some problems associated with price, stability, toxicity, pollution, waste treatment, reaction conditions, etc. On the other hand, metal free organocatalytic reactions avoid such problems and reactions can be performed in aerobic conditions with wet solvents. Several examples illustrating these catalytic approaches are given in this chapter. Chapter 2: Synthesis and Characterization of Sugar-based Organocatalysts This chapter deals with the synthesis and characterization ofglucosamine derivatives and their corresponding prolinamides. Since sugar-based amino alcohols are leading source of contiguous stereogenic centers bearing primary amino group and hydroxyl group(s) that may be......................