Polythiacrown macro- and gigantocycles with chiral diacetal cores
Polythiacrown macro- and gigantocycles with chiral diacetal cores
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DOI：
10.1002/ejoc.200601045
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发表时间：
2007-04-01
影响因子：
2.8
通讯作者：
Fuchs, Benzion
中科院分区：
文献类型：
--
作者：
Abramson, Sarah;Berkovich-Berger, Dvora;Fuchs, Benzion
我们提出了一类独特的聚硫杂冠醚大环和杂环（[9]）体系，该体系由1 - 6个顺式-1，3，5，7-四氧萘烷（TOD）型二缩醛单元上的乙烯-1，2-二硫代乙二醇（ETG）与聚（乙硫基乙二醇）（ETG（n））桥连组成。后者是一个不对称的手性部分，包含一个具有内置高电子孤对浓度的空腔，作为手性大环主体系统的“核心”，具有良好的离子和极性分子的包合能力。我们描述两种方法：（一）2，6-双的反应在Cs2 CO 3促进的过程中，使（溴甲基）-顺式-TOD podand（6）与ETG或更高的ETG（n）s（12（n））反应，导致通过开放的二硫醇中间体先天但不受控制地形成ETG/TOD比为1：1（7）、2：2（8）和另外的3：3-6：6（11（l/m））大环的聚硫杂冠状-TOD大环，和（ii）使用K2 CO 3明智地制备ETG（n）：TOD比为1：2、2：3或3：1的低聚二溴化物中间体。4（14（n/m）），其以受控的方式（与另外的ETG（n））导致2：2（8（n））或3：3、4：4和6：6（11（n/m））大环和双环体系。总之，这些过程的结果取决于反应物的相对浓度。合成伴随有详细的（NMR和MS）光谱。X-射线晶体学分析的大环化合物的数量，补充（MM和MD）计算，可能有价值的结构，立体化学和构象分析。虽然复杂的立体化学特征，这些系统很容易制备的对映体纯的形式，并持有很大的希望，在金属离子包合和分子和手性识别的化学反应性。((C)Wiley-VCH Verlag GmbH & Co. KGaA，69451魏因海姆，德国，2007）。
We present a unique class of polythiacrown macro- and gigantocyclic([9]) systems, consisting of ethylene 1,2-dithioglycol (ETG) to poly(ethylene thioglycol) (ETG(n)) bridges over one to six diacetal units of the cis-1,3,5,7-tetraoxadecalin (TOD) type. The latter is a dissymmetric, chiral moiety, incorporating a cavity with built-in high electron lone pair concentration, serving as the "core" of chiral macrocyclic host systems with good inclusion ability of ions and polar molecules. We describe two approaches: (i) the reactions of the 2,6-bis(bromomethyl)-cis-TOD podand (6) with ETG or higher ETG(n)s (12(n)), in Cs2CO3 promoted processes, leading to the innate but uncontrolled formation of polythiacrown-TOD macrocycles having ETG/TOD ratios of 1:1 (7), 2:2 (8) and further 3:3-6:6 (11(1/m)) macrocycles via open dithiol intermediates, and (ii) judicious preparation, using K2CO3, of oligomeric dibromide intermediates with ETG(n):TOD ratios 1:2, 2:3 or 3:4 (14(n/m)), which led (with further ETG(n)) in a controlled way to the 2:2 (8(n)), or 3:3, 4:4 and 6:6 (11(n/m)) macro- and gigantocyclic systems, Altogether, the outcome of these processes depends on the relative concentrations of the reactants. Synthesis was accompanied by detailed (NMR and MS) spectroscopy. X-ray crystallographic analysis of a number of macrocycles, complemented by (MM & MD) computation, made possible valuable structural, stereochemical and conformational analysis. While sophisticated in their stereochemical features, these systems are readily prepared in enantiopure form and hold great promise of chemical reactivity in metal ion inclusion and molecular and chiral recognition. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).