Synthesis of higher sugars

Abstract

This thesis deals with the synthesis of higher sugars using two methodologies, namely, 1) Wadsworth-Emmons reaction and 2) /erra-hydroxylation of sugar derived dienes. The thesis consists of three sections, namely, introduction, results and discussion and experimental. The results and discussion is divided into two parts. Part-1 deals with preparation of sugar derived p keto phosphonates and their use in the synthesis of higher sugars. Part-n deals with synthesis of higher sugars by iw-dihydroxylation of sugar dienes. The introduction briefly presents various available methods for the synthesis of higher sugars. Different approaches, which are commonly used are discussed under six major headings, namely, 1) Wittig reaction, 2) Aldol condensation, 3) Radical reactions, 4) Nucleophilic additions, 5) (3+2) Cycloaddition and 6) Ab-initio synthesis. Synthesis of higher sugars has been a target of interest to the organic chemist since the time of Fischer. This is due to the fact that higher sugars are, a) complex carbohydrates, which are not available in nature, b) components of some natural products like hikizimycin and tunicamycin and c) chiral, highly functionalized synthons for the preparation of macrolide antibiotics like erythromycin and streptovaricin. Synthesis of higher sugars using Wadsworth Emmons reaction.