Facile and robust methods for the regioselective acylation of N-acetylneuraminic acid.
Facile and robust methods for the regioselective acylation of N-acetylneuraminic acid.
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N-乙酰神经氨酸的区域选择性酰化的简便而可靠的方法。
DOI：
10.1039/c8nj02795a
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
DeMeo,Cristina
中科院分区：
文献类型：
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作者：
Shadrick,Melanie;Yu,Charlene;Geringer,Scott;Ritter,Sean;Behm,Alexanndra;Cox,Abby;Lohman,Matt;DeMeo,Cristina
唾液酸糖缀合物的立体选择性合成仍然是该领域的一个挑战。令人惊讶的是，很少有人知道唾液酸的区域选择性O-取代。因此，O-保护基团和/或区域选择性保护的结构单元对唾液酸化的影响实际上仍然未被探索。O-皮可酰基保护基团已经作为对唾液酸化具有深远影响的新型取代基出现。最近，通过在C-4和C-7/C-8位引入皮考酰基获得了高立体选择性。然而，为了理解皮考酰基的位置与其对唾液酸化的确切影响之间的关系，需要一种方便的方法来获得更广泛的区域选择性皮考酰化的结构单元。本文报道了一种新的方法，该方法提供了一种获得大量区域选择性酰化结构单元的途径。通过控制直接皮考酰化或通过应用改进的ReSET方法，实现了在各个O-位置的皮考酰基团的区域选择性引入。
The stereoselective synthesis of sialic acid glycoconjugates is still a challenge in the field. Surprisingly, little is known on the regioselective O-substitution of sialic acids. Consequently, the effect of O-protecting groups and/or regioselectively protected building blocks on sialylations remains practically unexplored. O-Picoloyl protecting groups have emerged as novel substituents that have a profound effect on sialylations. Recently, high stereoselectivities were obtained by introducing picoloyl groups at the C-4 and C-7/C-8 positions. However, to understand the relationship between the position of the picoloyl group and its exact effect on sialylations, a convenient method to access to a wider range of regioselectively picoloylated building blocks is needed. Herein, a new method that provides an accessible route to a wide array of regioselectively acylated building blocks is reported. The regioselective introduction of picoloyl groups at various O-positions was achieved either by controlled direct picoloylation or by applying a modified ReSET methodology.