甜菊糖苷的高效合成研究

As a new type of natural sweetener, steviol glycosides are preferably welcomed by the consumers due to their highly-sweet, noncalorific, and safe properties. Therefore, as additives they are widely applied in food industry. Nevertheless, the unsatisfactory taste of the existing steviol glycoside sweeteners as well as the difficulty associated with quality-control for steviol glycosides-making companies calls on the highly efficient synthesis of these glycoconjugates. In this project, we plant to establish an efficient and diversity-oriented synthetic route toward the general members of steviol glycosides with glycosyl alkynylbenzoate as glycosyl donors, which will facilitate the synthesis of their analogues. Meanwhile, taking full advantage of the efficient remote-control potential of DMNA, a universal protocol for stereoselective construction of glucosyl 1,2-syn-glycosidic linkage will be set up, based on which the first total synthesis of the novel and minor numbers of steviol glycosides, rebaudioside R and S will also be accomplished. The implement of this program will not only expedite the development process of new sweeteners but also provide authentic samples to stevoil glycoside-making companies for the establishment of more reliable quality-control systems. Therefore both the theoretical and practical significances of the project are profound.

甜菊糖苷是一类重要的天然甜味剂，因其甜度高、热量低且安全性好等特点而受到消费的青睐，因此作为添加剂广泛应用于食品工业之中。然而现有甜菊糖苷并不理想的口感以及甜菊糖苷生产企业的产品的可靠质量控制均呼唤甜菊糖类化合物的高效合成。本课题拟利用糖基炔酯给体建立常见甜菊糖苷的多样化合成路线，为其类似物的合成奠定基础。同时利用新型保护基DMNA的远程参与作用确立高效合成葡萄糖1,2-顺式糖苷键的方法，并在此基础上完成两个新型低含量甜菊糖苷rebaudioside R和S的合成。通过本课题的实施不仅将加快新型理想甜菊糖苷类甜味剂的研发、为甜菊糖苷生产企业建立可靠质量控制体系提供标样，同时可以进一步丰富二萜皂苷的合成理论，因此具有重要的理论和现实意义。

甜菊糖苷是一类重要的天然甜味剂，因其甜度高、热量低且安全性好等特点而受到消费的青睐，因此作为添加剂广泛应用于食品工业之中。然而现有甜菊糖苷并不理想的口感以及甜菊糖苷生产企业的产品的可靠质量控制均呼唤甜菊糖类化合物的高效合成。本课题利用糖基炔酯给体不仅建立了包括Rebaudioside A, D, M, R和S在内的多类甜菊糖苷的多样化合成路线，为其进一步应用开发奠定了坚实的基础，还通过化学合成修正了Rebaybioside S的化学结构。通过本课题的实施不仅加快了新型理想甜菊糖苷类甜味剂的研发、为甜菊糖苷生产企业建立可靠质量控制体系提供标样，也进一步丰富了二萜皂苷的合成理论。