Stereoselective assembly of complex oligosaccharides using anomeric sulfonium ions as glycosyl donors.
Stereoselective assembly of complex oligosaccharides using anomeric sulfonium ions as glycosyl donors.
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DOI：
10.1021/ja3018187
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发表时间：
2012-05-02
影响因子：
15
通讯作者：
Boons, Geert-Jan
中科院分区：
文献类型：
--
作者：
Fang, Tao;Mo, Kai-For;Boons, Geert-Jan
开发选择性保护的单糖结构单元，可以可靠地与各种各样的受体糖基化，预计将使寡糖合成更常规的操作。特别是，迫切需要开发模块化结构单元，其可以容易地转化为糖基供体用于糖基化，从而提供可靠的高1，2-顺式-异头选择性。我们在这里报告，1，2-氧硫杂环丁烷醚是稳定的酸性，碱性和还原条件下，使其能够进行广泛的保护基团的操作和安装选择性可去除的保护基团，如乙酰丙酰基（Lev）酯，芴基甲氧基-（Fmoc）和烯丙氧基-（Alloc）碳酸酯，和2-甲基萘基醚（Nap）。氧硫杂环丁烷醚可以很容易地被氧化成亚砜，并与1，3，5-三甲氧基苯芳基化为双环异头锍离子。得到的锍离子得到高的1，2-顺式异头选择性时，糖基化与各种各样的糖基受体，包括适当保护的氨基酸，伯和仲糖醇和部分保护的硫代糖苷。选择性保护的1，2-氧硫杂环己烷被成功地用于制备衍生自从真菌Pseudallescheria boydii分离的糖原样多糖的支链葡糖苷，其参与真菌吞噬作用和先天免疫应答的激活。该化合物是通过潜在的活性糖基化策略组装的，其中氧硫杂环己烷在与亚砜供体的糖基化中用作受体。这种糖基化的产物被氧化成亚砜用于随后的糖基化。使用Nap和Fmoc作为临时保护基团使得可以安装分支点。
The development of selectively protected monosaccharide building blocks that can reliably be glycosylated with a wide variety of acceptors is expected to make oligosaccharide synthesis a more routine operation. In particular, there is an urgent need for the development of modular building blocks that can readily be converted into glycosyl donors for glycosylations that give reliably high 1,2-cis-anomeric selectivity. We report here that 1,2-oxathiane ethers are stable under acidic, basic, and reductive conditions making it possible to conduct a wide range of protecting group manipulations and install selectively removable protecting groups such as levulinoyl (Lev) ester, fluorenylmethyloxy- (Fmoc) and allyloxy- (Alloc) carbonates, and 2-methyl naphthyl ethers (Nap). The 1,2-oxathiane ethers could easily be converted into bicyclic anomeric sulfonium ions by oxidization to sulfoxides and arylated with 1,3,5-trimethoxybenzene. The resulting sulfonium ions gave high 1,2-cis anomeric selectivity when glycosylated with a wide variety of glycosyl acceptors including properly protected amino acids, primary and secondary sugar alcohols and partially protected thioglycosides. The selective protected 1,2-oxathianes were successfully employed in the preparation of a branched glucoside derived from a glycogen-like polysaccharide isolated form the fungus Pseudallescheria boydii, which is involved in fungal phagocytosis and activation of innate immune responses. The compound was assembled by a latent-active glycosylation strategy in which an oxathiane was employed as an acceptor in a glycosylation with a sulfoxide donor. The product of such a glycosylation was oxidized to a sulfoxide for a subsequent glycosylation. The use of Nap and Fmoc as temporary protecting groups made it possible to install branching points.
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碳水化合物化学中的保护基团：对糖基化立体选择性的影响
DOI：
10.3390/molecules15107235
发表时间：
2010-10-20
期刊：
Molecules (Basel, Switzerland)
影响因子：
--
作者：
Guo J;Ye XS
通讯作者：
Ye XS
影响因子：
15
作者：
Arungundram, Sailaja;Al-Mafraji, Kanar;Asong, Jinkeng;Leach, Franklin E., III;Amster, I. Jonathan;Venot, Andre;Turnbull, Jeremy E.;Boons, Geert-Jan
通讯作者：
Boons, Geert-Jan
影响因子：
4.8
作者：
Figueiredo, Rodrigo T.;Fernandez, Patricia L.;Bozza, Marcelo T.
通讯作者：
Bozza, Marcelo T.
影响因子：
4.8
作者：
Bittencourt, Vera Carolina B.;Figueiredo, Rodrigo T.;Barreto-Bergter, Eliana
通讯作者：
Barreto-Bergter, Eliana
影响因子：
3.6
作者：
Ellervik, U;Grundberg, H;Magnusson, G
通讯作者：
Magnusson, G