壹、溶劑參與效應醣基化反應一鍋化策略; 貳、2-疊氮-2去氧醣予體合成天然寡醣

Abstract

本論文分為兩大部分: 1. 在建構 beta-選擇性醣苷鍵策略中，溶劑參與效應一鍋化醣質化反應 (SPOG) 已被普遍使用在低濃度腈類混和溶劑反應系統中。這種策略可在一鍋化策略的情況下控制生成良好的 立體選擇性。同時，我們更衍生應用於正交醣基化反應策略，將醣基磷酸酯予體及硫醣受體搭配，經由一鍋化的方式合成產率極佳的寡醣分子。

2. 葡萄糖胺是一種和人類息息相關重要醣分子之一，一般含有胺基或是乙醯基保護的胺基。而三疊氮 (azido，N3) 保護基可在溫和的情況下被還原去保護，並且因為三疊氮保護基缺乏鄰助基效應一般常被用來使用製備beta 醣苷鍵。我們發展了具備高產率及良好的1,2-反式 beta-選擇性的溶劑鄰助基策略，使用在2-三疊氮-去氧葡萄糖胺予體上，並且成功的得到與生物有關的F1-apha前驅物以及(1,6)-beta葡萄糖胺寡醣鏈。

This thesis is divide into two parts:

1. Solvent participating one-pot glycosylation (SPOG) strategy was developed on the base of low concentration beta-selective glycosylation method. This strategy enables the control of stereochemistry in one-pot glycosylations through solvent addition. Meanwhile, further application of the low concentratnion glycosylation (LCG) to orthogonal glycosylation strategy is explored. Combining glycosyl phosphates and thioglycosides, oligosaccharides could be synthesized in a one-pot manner to furnish in good yield and excellent stereoselectivity.

2. Glucosamine is one of the major amino sugars present in human-related oligosaccharides, which contain an amino group (or acetamido) at the C-2 position. The azido function can readily be reduced to amine under mild conditions. Due to the non-participation nature, 2-azido-2-deoxy glycosyl donors are mandatory substrates for construction of 1,2-cis apha-glycosidic bond under specific reaction condition We developed a high-yielding and stereocontolled construction of 1,2-trans-beta-glycosidic linkages with 2-azido-2- deoxy glycopyranosyl donors using the solvent participated one-pot glycosylation strategy. We successfully prepared some biological relevant oligosaccharide targets such as F1-apha precursor trisaccharide, and beta-(1,6) glucosamine.