Stereoselective oxidative glycosylation of anomeric nucleophiles with alcohols and carboxylic acids.
Stereoselective oxidative glycosylation of anomeric nucleophiles with alcohols and carboxylic acids.
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DOI：
10.1038/s41467-018-06016-4
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发表时间：
2018-09-07
影响因子：
16.6
通讯作者：
Walczak MA
中科院分区：
文献类型：
--
作者：
Yang T;Zhu F;Walczak MA
低聚糖是一种含量最丰富的生物聚合物，参与多种生物过程。尽管在制备碳水化合物化学方面已经付出了许多努力，但实现最佳的异构体和区域选择性仍然具有挑战性。在这里，我们描述了一种异构体锡烷和氧亲核试剂之间的氧化糖基化方法，对于含有自由C2-羟基的糖基供体，导致形成具有一致高异构体控制性的C-−O键。这些反应由高价碘试剂与催化量或化学计量比的铜或锌盐促进。42个例子说明了这种变换的一般性。机理研究表明，氧化糖基化是由高价碘和对甲苯磺酸盐在羟基的引导下进入异构体位置而引发的，具有很好的1，2-反式选择性。独特的反应机理、高选择性和温和的反应条件使该方法适用于低聚糖的合成以及与其他方法的集成，如自动合成。部分保护的糖的糖基化通常受到次优的区域和立体选择性的限制。在这里，作者展示了具有不受保护的羟基的异构体锡烷与氧亲核试剂之间的一般氧化糖基化反应，此外还提供了对选择性来源的机械见解。
Oligosaccharides, one of the most abundant biopolymers, are involved in numerous biological processes. Although many efforts have been put in preparative carbohydrate chemistry, achieving optimal anomeric and regioselectivities remains challenging. Herein we describe an oxidative glycosylation method between anomeric stannanes and oxygen nucleophiles resulting in the formation of a C−O bond with consistently high anomeric control for glycosyl donors bearing a free C2-hydroxyl group. These reactions are promoted by hypervalent iodine reagents with catalytic or stoichiometric amounts of Cu or Zn salts. The generality of this transformation is demonstrated in 42 examples. Mechanistic studies indicate that the oxidative glycosylation is initiated by the hydroxyl-guided delivery of the hypervalent iodine and tosylate into the anomeric position, and results in excellent 1,2-trans selectivity. The unique mechanistic paradigm, high selectivities, and mild reaction conditions make this method suitable for the synthesis of oligosaccharides and for integration with other methodologies such as automated synthesis. Glycosylation of partially protected sugars is usually limited by suboptimal regio- and stereo-selectivities. Here, the authors show a general oxidative glycosylation between anomeric stannanes with a nonprotected hydroxyl group and oxygen nucleophiles, additionally providing mechanistic insights into the origin of selectivity.
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影响因子：
16.6
作者：
Le Mai Hoang K;He JX;Báti G;Chan-Park MB;Liu XW
通讯作者：
Liu XW
影响因子：
2.8
作者：
Kristensen, Steffan K.;Salamone, Stephane;Jensen, Henrik H.
通讯作者：
Jensen, Henrik H.
影响因子：
5.2
作者：
Du, YG;Gu, GF;Linhardt, RJ
通讯作者：
Linhardt, RJ
影响因子：
3.6
作者：
GERVAY, J;PETERSON, JM;DANISHEFSKY, SJ
通讯作者：
DANISHEFSKY, SJ
影响因子：
5.2
作者：
Kim, JY;Di Bussolo, V;Gin, DY
通讯作者：
Gin, DY