Chapter 10 - Diastereomeric transition states and stereoselectivity

Abstract

This chapter presents components of different types of Dynamic stereochemistry. All types of stereoselective processes including stereospecific reactions, substrate-controlled/reagent-controlled/catalyst-controlled Asymmetric synthesis have been illustrated. Chiral Auxiliary approach has been illustrated. The importance of diastereomeric transition states in stereoselective transformations have been discussed. Discussion on Cram’s rule with Felkin-Ahn model and Zimmerman-Traxler model has been provided. Double stereo-differentiation has been discussed with examples. A few selected asymmetric processes, illustrating the parameters of efficient asymmetric synthesis have been presented. The discussion on Asymmetric Aldol reaction, Sharpless epoxidation, Jacobsen-Katsuki epoxidation, enantio-selective dihydroxylation, enantioselective amino-hydroxylation, Enantioselective carbonyl reductions using BINAL-H, chiral borane reagents, CBS reagent, homogeneous asymmetric catalysis, asymmetric allylamine to enamine isomerisation, asymmetric Diels-Alder reaction and chiral organo-catalysis has been provided. The proposed/established mechanisms, catalytic cycles have been provided wherever required. Selected applications of each methodology in accessing natural products, bioactive products have been provided.