Ortho ester Claisen rearrangements of three 3-C-(hydroxymethyl)methylene derivatives of hexofuranose: stereoselective introduction of a quaternary center on C-3 of D-ribo-, L-lyxo-, and D-arabino-hexofuranoses
Ortho ester Claisen rearrangements of three 3-C-(hydroxymethyl)methylene derivatives of hexofuranose: stereoselective introduction of a quaternary center on C-3 of D-ribo-, L-lyxo-, and D-arabino-hexofuranoses
复制标题
呋喃己糖的三种 3-C-（羟甲基）亚甲基衍生物的原酸酯克莱森重排：在 D-核糖-、L-lyxo-和 D-阿拉伯-呋喃己糖的 C-3 上立体选择性引入季中心
DOI：
10.1021/jo00383a005
复制
发表时间：
1987
影响因子：
3.6
通讯作者：
T. Suami
中科院分区：
文献类型：
--
作者：
K. Tadano;Yoko Idogaki;H. Yamada;T. Suami
(2？)-3-脱氧-3-C-[(羟甲基)亚甲基]-L，2：5，6-二-0-异亚丙基-六氟呋喃(3-2？)，-dL-齐氧-六氟碳糖(12-2？)和-DD-甲氧基-六氟呋喃糖(33-2？)以高的立体选择性进行，分别以可接受的产率提供重排产物13、15和34。还研究了相应的Z异构体3-Z、12-Z和33-Z的重排反应。通过对每个重排产物进行化学修饰，明确地建立了化合物13、15和34的C-3上新引入的四元中心的立体化学结构。在有机合成中，特别是在天然产物的合成中，在碳骨架的适当位置引入四元中心是一个经常遇到的问题。对于这一关键问题，近年来报道了几种所谓的解决方案。其中，Claisen重排策略是一种有效而便捷的策略。在许多情况下，重排反应具有很高的立体选择性。作为Claisen重排反应的变种之一，邻位酯类Claisen重排反应是在同一碳原子上同时引入一个(烷氧羰基)甲基和一个乙烯基团的有效方法。在许多情况下，这些功能可以通过相当简单的操作转换为其他功能。以碳水化合物、萜类和氨基酸等容易获得的光学纯化合物作为手性起始原料，已经实现了许多合成天然产物的优雅的合成方法。3 Fraser-Reid和他的同事最近报道了一些已吡喃糖衍生物的Claisen重排([3.3]-烯丙基乙烯基醚型重排)，并实现了四元中心的引入。4利用六元环模型实现了四元中心的高立体选择性引入。我们自己的兴趣是通过研究五元环模型的重排来获得立体选择性，也就是一些呋喃糖模型。
Ortho ester Claisen rearrangements of (2?)-3-deoxy-3-C-[(hydroxymethyl) methylene]-l, 2: 5, 6-di-0-iso-propylidene-aD-ribo-hexofuranose (3-2?),-dL-Zyxo-hexofuranose (12-2?), and-dD-orobino-hexofuranose (33-2?) proceeded with high stereoselectivity to provide the rearranged products 13, 15, and 34, respectively, in acceptable yields. The rearrangements of the corresponding Z isomers 3-Z, 12-Z, and 33-Z were also investigated. The stereochemistries of the newly introduced quaternary center on C-3 of compounds 13, 15, and 34 were established unambiguously by chemical modifications of each rearrangedproduct.Introduction of a quaternary center in an appropriate position of the carbon framework is a frequently encoun-tered problem in organic synthesis, especially in natural product synthesis. For this crucial problem, several so-phisticated solutions were reported in recent years. 1 Among these, the Claisen rearrangement approach is an effective and convenient strategy. In many cases, the rearrangement proceeds with high stereoselectivity. Ortho ester Claisen rearrangement, one of the variants of the Claisen rearrangement, is a useful procedure for simulta-neous introduction of an (alkoxycarbonyl) methyl group and a vinyl group on the same carbon. 2 These functionalities are, in many cases, convertible to other function-alities by rather simple operations. A number of elegant synthetic approaches to natural product synthesis have been achieved that employ readily available optically purecompounds such as carbohydrates, terpenes, and amino acids as chiral starting materials. 3 Fraser-Reid and coworkers recently reported the Claisen rearrangement ([3.3]-allyl vinyl ether type rearrangement) of some hexopyranose-derived compounds and achieved introduction of the quaternary centers on hexopyranoses, 4 realizing highly stereoselective introduction of the qua-ternary center by using six-membered cyclic models. Our own interest is in gaining stereoselectivity by studying the rearrangement of five-membered cyclic models, that is, some furanose models.