A recyclable heavy fluorous tag carrying an allyl alcohol pendant group: design and evaluation toward applications in synthetic carbohydrate chemistry
A recyclable heavy fluorous tag carrying an allyl alcohol pendant group: design and evaluation toward applications in synthetic carbohydrate chemistry
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DOI：
10.1016/j.carres.2015.02.002
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发表时间：
2015-04-30
影响因子：
3.1
通讯作者：
Mizuno, Mamoru
中科院分区：
文献类型：
--
作者：
Fukuda, Kazuo;Tojino, Mami;Mizuno, Mamoru
为了在合成碳水化合物化学中的应用，我们通过烯烃交叉复分解将我们以前的耐酸重氟标记[（Rf）（3）C-CH 2-OH，1]转化为烯丙醇衍生物[（Rf）（3）C-CH 2-O-（CH 2）（n）-CH= CH-CH 2-OH，3（n=1）或4（n=3）]。然后，通过使用一系列糖基供体，包括糖基溴和三氯乙酰亚胺酯，使它们进行β-糖基化反应。当使用2，3，4，6-四-O-苯甲酰基-D-半乳糖基三氯乙酰亚胺酯作为糖基供体时，发现3和4中的末端OH基团以中等产率被β-糖基化。在使用Pd（PPh 3）（4）的分离反应后，以高产率（>90%）回收了初始的重氟标记1以及1-羟基糖，表明不仅糖苷中的烯丙基醚键而且4中的内部二烷基醚键都通过Pd催化剂的作用裂解，从而能够实现长距离烯烃迁移。通过使用3的四-O-苯甲酰基-β-D-半乳糖基化衍生物在一系列脱保护、保护和糖基化反应中表现出潜在的实用性，这些反应可以在不使用色谱纯化过程的情况下以高产率进行。这些发现促使我们提出了一个总体方案，其中耐酸重氟化合物1被用作合成碳水化合物化学中的可回收标签。(C)2015爱思唯尔有限公司版权所有。
Toward applications in synthetic carbohydrate chemistry, we converted our previous acid-resistant heavy fluorous tag [(Rf)(3)C-CH2-OH, 1] to allyl alcohol derivatives [(Rf)(3)C-CH2-O-(CH2)(n)-CH=CH-CH2-OH, 3 (n=1) or 4 (n=3)] by means of olefin cross metathesis. They were then subjected to beta-glycosylation reactions by using a series of glycosyl donors, including glycosyl bromide and trichloroacetimidates. The terminal OH group in 3 and 4 was found to be beta-glycosylated in moderate yield when 2,3,4,6-tetra-O-benzoyl-D-galactosyl trichloroacetimidate was used as the glycosyl donor. Upon a detachment reaction using Pd(PPh3)(4), the initial heavy fluorous tag 1 was recovered in high yield (>90%) together with 1-hydroxy sugar, indicating that not only the allyl ether linkage in the glycosides but also the internal di-alkyl ether linkage in 4 be cleaved by the action of the Pd-catalyst enabling long-range olefin transmigration. Potential utility was demonstrated by using the tetra-O-benzoyl-beta-D-galactosylated derivative of 3 in a series of deprotection, protection and glycosylation reactions, which were conductible in high yields without using chromatographic purification process. These findings prompt us to propose a general scheme in which the acid-resistant heavy fluorous compound 1 is applied as a recyclable tag in synthetic carbohydrate chemistry. (C) 2015 Elsevier Ltd. All rights reserved.