DEVELOPMENT OF STEREOSELECTIVE AND ENANTIOSELECTIVE SYNTHESIS METHODS: FROM CLASSICAL APPROACHES TO MODERN CATALYTIC SYSTEMS

This article presents a comprehensive analysis of the development and advancement of stereoselective and enantioselective synthesis methods in organic chemistry. Stereocontrol in chemical synthesis has emerged as one of the most significant achievements in modern chemistry, enabling the preparation of enantiomerically pure compounds essential for pharmaceuticals, agrochemicals, and advanced materials. The study examines the evolution from classical resolution techniques to contemporary asymmetric catalysis, including asymmetric hydrogenation, epoxidation, dihydroxylation, and organocatalytic transformations. Historical development is traced from early stereochemical concepts through Nobel Prize-winning catalytic methods to current state-of-the-art approaches. Experimental evaluation of representative stereoselective reactions demonstrates the superiority of catalytic asymmetric methods over classical approaches, achieving enantiomeric excesses exceeding 99% with catalyst loadings as low as 0.01-1 mol%. The discussion emphasizes mechanistic understanding, catalyst design principles, and industrial applications. Results show that asymmetric catalysis has revolutionized pharmaceutical synthesis, with over 50% of marketed drugs requiring enantiopure intermediates. Modern organocatalysis and biocatalysis represent sustainable alternatives to traditional metal catalysis, achieving comparable selectivity with improved environmental profiles.