Exploring Palladium Chemistry in Carbohydrate Synthesis

本项目将重点发展一种直接从三氟乙酸糖基合成α -2,3-不饱和o -糖苷的新方法。该方法仅依赖于催化剂-糖络合的性质来控制异构中心的立体选择性。将进行研究以阐明这一反应的机理。该方法可用于维尼霉素及1,2-顺式苷类化合物的全合成。本提案的第二个方面是开发一种通过钯（II）催化三氯乙酸乙酯糖基重排合成α -和β -糖基脲的有效方法。今后将进一步研究催化剂的性质和重排机理。有了这个奖项，有机和大分子化学项目支持蒙大拿州立大学化学和生物化学系的Hien Nguyen教授的研究，以开发构建生物活性碳水化合物的有效方法。碳水化合物是自然界中结构最多样化的一类生物分子，现在已经确定它们在各种生物系统中的关键作用取决于低聚糖和其他大分子之间的特定相互作用。近年来，对糖基脲的研究逐渐兴起，并在氨基糖苷类抗生素领域得到了应用。

This proposed project will focus on the development of a new method for stereoselective synthesis of alpha-2,3-unsaturated-O-glycosides directly from glycal trichoroacetimidates. This approach relies only on the nature of the catalyst-glycal complexation to control the stereoselectivity at the anomeric center. Studies to elucidate the mechanism of this reaction will be undertaken. This method will be applied toward the total synthesis of vineomycin as well as 1,2-cis glycosides. The second aspect of this proposal is to develop an efficient method for the synthesis of alpha- and beta-glycosyl ureas via palladium(II)-catalyzed rearrangement of glycal trichloroacetimidates. Studies to further elucidate the nature of the catalysts as well as the mechanism of the rearrangement will be undertaken.With this award, the Organic and Macromolecular Chemistry Program is supporting the research of Professor Hien Nguyen of the Department of Chemistry and Biochemistry at Montana State University to develop efficient methods for constructing biologically active carbohydrates. Carbohydrates are the most structurally diverse class of biomolecules in nature, and it is now established that their critical roles in a variety of biological systems depend on the specific interactions between oligosacharides and other macromolecules. The research on the area of glycosyl ureas has recently emerged with applications in the field of aminoglycoside antibiotics.