Highly stereoselective addition of organozinc reagents to pentopyranose derived glycals:: effect of protecting group and assignment of C-glycoside stereochemistry
Highly stereoselective addition of organozinc reagents to pentopyranose derived glycals:: effect of protecting group and assignment of C-glycoside stereochemistry
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DOI：
10.1016/j.tet.2004.04.004
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发表时间：
2004-05-31
期刊：
影响因子：
2.1
通讯作者：
Gallagher, T
中科院分区：
文献类型：
--
作者：
Cook, MJ;Fletcher, MJE;Gallagher, T
乙基3-丙酰碘化锌与多种不同保护的吡喃戊糖衍生的D-糖苷6a-g的亲核加成以良好至高水平的非对映选择性进行，以提供相应的P-C-糖苷7。对硝基苯甲酸酯衍生物7d的立体化学已通过X射线晶体学证实，并且其他P-C-糖苷产物的立体化学已与7d相关。观察到的立体化学结果支持了 Isobe 早期的建议，即空间效应对于稳定和控制以 11 为代表的中间体氧鎓物种的反应性非常重要。(C) 2004 Elsevier Ltd. 保留所有权利。
The nucleophilic addition of ethyl 3-propionylzinc iodide to a variety of differently protected pentopyranose derived D-glycals 6a-g proceeds with good to high levels of diastereoselectivity to provide the corresponding P-C-glycosides 7. The stereochemistry of the para-nitrobenzoate derivative 7d has been confirmed by X-ray crystallography, and the stereochemistry of the other P-C-glycoside products has been correlated to 7d. The stereochemical outcome observed supports the earlier suggestion by Isobe that through-space effects are important in stabilising and controlling the reactivity of the intermediate oxonium species represented by 11. (C) 2004 Elsevier Ltd. All rights reserved.