壹、alpha-Galactosyl Ceramide與衍生物的合成; 發展苯基醣酐衍生物作為醣鏈結方法的研究與掩飾鄰苯醌的分子內不對稱Diels-Alder反應研究

Synthesis of α-galactosyl ceramide and its derivatives; Development of phenyl glycosides in the studies of new glycosylation methods and asymmetric intramolecular diels-alder reactions of masked ο-Benzoquinones

羅順原(Shun-Yuan Luo)

指導教授 ： 洪上程

國立清華大學/理學院/化學系/博士(2008年)

https://doi.org/10.6843/NTHU.2008.00326

摘要

碳水化合物在許多的生物機制中扮演著非常重要的角色，而利用化學合成的方法可以大量取得結構確定且高純度的醣類分子。在本論文中，第一部份是探討□-galactosyl ceramide與其衍生物的合成。首先介紹利用D-葡萄醣胺來製備phytosphingosine衍生物，經與半乳糖結合後，進而合成出□-galactosyl ceramide；其次是描述此新開發的途徑應用來製備□-galactosyl ceramide第六號碳的衍生物。第二部份是研發苯基醣酐衍生物作為醣鏈結的新方法與掩飾鄰苯醌的分子內不對稱Diels-Alder反應研究。首先介紹兩種新型的苯基醣酐衍生物作為醣予體的反應研究，經由不同的活化劑，可與多種醣受體進行醣鏈結反應，並且可應用來合成出博菜黴素的前驅雙醣體。其次是報導醣作為掌性輔助基進行掩飾鄰苯醌的合成及分子內Diels-Alder的反應研究，並且利用已知化合物之X-光單晶繞射圖及旋光值來比對新化合物的絕對立體組態。此掩飾鄰苯醌分子內不對稱Diels-Alder反應可應用在不同烯醇化合物，得到多種三環烯酮產物。

關鍵字

合成 ； 掩飾鄰苯醌 ； 苯基醣酐 ； HASH(0x1b026a80)

並列摘要

Carbohydrates play important roles in many biological processes. Chemical synthesis may offer a good solution to get the pure and structurally verified oligosaccharides. The first part of this thesis describes the synthesis of □-galactosyl ceramide and its C6-derivatives. The phytosphingosine derivative, which was obtained from D-glucosamine, could used to prepare □-galactosyl ceramide. This strategy can be applied to prepare a variety of a-galactosyl ceramide C6-derivatives. The second part is concerned with the development of phenyl glycosides in the studies of new glycosylation methods and asymmetric intramolecular Diels-Alder reactions of masked o-benzoquinones. Two new and stable types of glycosyl donors, namely 2-allylphenyl and 2-allyloxyphenyl glycosides, were successfully developed, and their coupling with various alcohols in good yields were further investigated. Ease of preparation, handling and storage together with simple reaction set up, and clean glycosylations make these glycosides as attractive donors for the synthesis of oligosaccharides and glycoconjugates, as illustrated by the construction of bleomycin disaccharide. The studies on the synthesis of masked o-benzoquinones embedded with glycopyranoside as chiral auxiliaries to induce new chirality and high diastereoselectivity in asymmetric intramolecular Diels-Alder reaction are also described. The absolute configuration of new compounds is determined by comparison with the X-ray analysis of known compounds and optical rotation values. This convenient methodology can be applied in a wide range of alkenols to prepare a variety of chiral tricyclic ketones.

並列關鍵字

Galactosyl Ceramide ； Diels-Alder ； Phenyl Glycosides ； Asymmetric

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