Synthesis of sialic acid derivatives based on chiral substrate-controlled stereoselective aldol reactions using pyruvic acid oxabicyclo[2.2.2]octyl orthoester
Synthesis of sialic acid derivatives based on chiral substrate-controlled stereoselective aldol reactions using pyruvic acid oxabicyclo[2.2.2]octyl orthoester
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使用丙酮酸氧杂二环[2.2.2]辛基原酸酯基于手性底物控制的立体选择性羟醛反应合成唾液酸衍生物
DOI：
10.1039/c6ob02412b
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Norimura;Y.; Yamamoto;D.; Makino;K.
基于底物控制的不对称羟醛缩合反应，合成了唾液酸及其类似物，该反应发生在由市售碳水化合物容易制备的空间复杂的醛和一种新型的水杨酸氧杂双环[2.2.2]辛基原酸酯之间。系统研究了手性醛的羟醛缩合反应，发现α，β，γ-苄氧基取代的α，β-反式醛优先生成具有4，5-反式构型的Felkin产物，具有较高的非对映选择性。α，β，γ-苄氧基取代醛的α，β-syn构型对Aldol反应中形成的立体中心的非对映选择性具有次要影响，α，β-syn-β，γ-anti苄氧基醛对α，β-syn-β，γ-syn苄氧基醛具有上级非对映选择性，生成Felkin产物。
The synthesis of sialic acids and their analogs was accomplished based on substrate-controlled asymmetric aldol reactions between sterically complicated aldehydes easily prepared from commercially available carbohydrates and a novel pyruvic acid oxabicyclo[2.2.2]octyl orthoester. Systematic aldol reaction studies using chiral aldehydes revealed that α,β,γ-benzyloxy-substituted aldehydes with an α,β-anti relative configuration preferentially provided the Felkin products with the 4,5-anti configuration with high diastereoselectivity. The relative β,γ-configuration in α,β,γ-benzyloxy-substituted aldehydes with an α,β-syn arrangement exerted a secondary effect on the diastereoselectivity of the stereogenic center formed in aldol reactions, and α,β-syn-β,γ-anti benzyloxyaldehyde exhibited superior diastereoselectivity to α,β-syn-β,γ-syn benzyloxyaldehyde to yield the Felkin products.