Gold(I)-Catalyzed Glycosylation with Glycosyl ortho-Alkynylbenzoates as Donors: General Scope and Application in the Synthesis of a Cyclic Triterpene Saponin
Gold(I)-Catalyzed Glycosylation with Glycosyl ortho-Alkynylbenzoates as Donors: General Scope and Application in the Synthesis of a Cyclic Triterpene Saponin
复制标题
以糖基原炔基苯甲酸酯为供体的金（I）催化糖基化：环状三萜皂苷合成的一般范围和应用
DOI：
10.1002/chem.200902548
复制
发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Yu, Biao
中科院分区：
文献类型：
--
作者：
Li, Yao;Yang, Xiaoyu;Yu, Biao
邻炔基苯甲酸糖基酯已经成为在金（I）络合物如Ph（3）PAuOTf和Ph（3）PAuNTf（2）（Tf=三氟甲磺酸盐）催化下的糖苷化的新一代供体。各种各样的这些供体，包括2-脱氧糖和唾液酸供体，容易制备并且储存稳定。与醇的糖苷偶联产率通常是优异的;甚至与弱亲核性酰胺的直接偶联也给出令人满意的产率。此外，已经实现了用2-脱氧糖供体的优异的α-选择性糖基化和β-选择性唾液酸化。本糖基化方案在环状三萜四糖的有效合成中的应用进一步证明了这种新方法的通用性和功效，因为已经实施了羧酸的新的化学选择性糖基化和新的一锅顺序糖基化序列。
Glycosyl ortho-alkynylbenzoates have emerged as a new generation of donors for glycosidation under the catalysis of gold(I) complexes such as Ph(3)PAuOTf and Ph(3)PAuNTf(2) (Tf= trifluoromethanesulfonate). A wide variety of these donors, including 2-deoxy sugar and sialyl donors, are easily prepared and shelf stable. The glycosidic coupling yields with alcohols are generally excellent; even direct coupling with the poorly nucleophilic amides gives satisfactory yields. Moreover, excellent alpha-selective glycosylation with a 2-deoxy sugar donor and beta-selective sialylation have been realized. Application of the present glycosylation protocol in the efficient synthesis of a cyclic triterpene tetrasaccharide have further demonstrated the versatility and efficacy of this new method, in that a novel chemoselective glycosylation of the carboxylic acid and a new one-pot sequential glycosylation sequence have been implemented.