Abstract
Carbohydrates are the key factors of many important biological processes. Chemical synthesis is one of the most practical ways to obtain the pure and structurally verified oligosaccharides. However, it is challenging for chemists, because of the inevitable regioselective protection of the polyhydroxyls and the stereoselective formation of every glycosidic bond.In this thesis, we aim at the development of a combinatorial, regioselective, orthogonal and one-pot methodology for the regioselective protection of the individual hydroxyl group of a monosaccharide in a single reaction vessel, and the so formed building blocks are assembled into biologically important □-1,6-glucans and influenza virus-binding trisaccharide library via a one-pot approach.A brief introduction to the background of glycobiology is described in chapter 1. Chapter 2 presents the traditional strategies for the protection of various monosaccharides, and chapter 3 reviews the methods for the classical glycosylation reactions as well as the recent advances in one-pot sequential glycosylations. In chapter 4, the specific aims of this thesis are described. The principle, conditions, physical data and the proposed mechanisms for the one-pot protection of monosaccharide are described in chapter 5. Hundreds of building blocks could be efficiently synthesized starting form a simple sugar. Chapter 6 exhibits the applications to the one-pot synthesis□of□□-1,6-glucans and influenza virus-binding trisaccharide library, and a brief conclusion is summarized in chapter 7. The detail experimental section and a list of references are described in chapters 8 and 9, respectively.