Recognition by new symmetrically substituted chiral diphenyl- and di-tert-butylpyridino-18-crown-6 and asymmetrically substituted chiral dimethylpyridino-18-crown-6 ligands of the enantiomers of various organic ammonium perchlorates
Recognition by new symmetrically substituted chiral diphenyl- and di-tert-butylpyridino-18-crown-6 and asymmetrically substituted chiral dimethylpyridino-18-crown-6 ligands of the enantiomers of various organic ammonium perchlorates
复制标题
通过新的对称取代的手性二苯基和二叔丁基吡啶基-18-冠-6和不对称取代的手性二甲基吡啶基-18-冠-6配体识别各种有机高氯酸铵的对映体
DOI：
10.1021/jo00010a028
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发表时间：
1991
影响因子：
3.6
通讯作者：
S. Lifson
中科院分区：
文献类型：
--
作者：
P. Huszthy;J. Bradshaw;C. Zhu;R. Izatt;S. Lifson
合成了三个新的手性吡啶-18-冠-6配体。这些配体在手性大环碳原子上含有两个苯基、两个叔丁基或两个甲基取代基。并合成了手性二叔丁基取代双酯冠醚类似物。制备两种二叔丁基取代冠醚所需的起始手性二叔丁基取代四甘醇由手性叔丁基-1，2-乙烷酮获得，其从其双（邻苯二甲酸氢）马钱子碱盐拆分。用变温~ 1H NMR方法测定了[α-（1-萘基）乙基]高氯酸铵（NapEt）对映体的活化自由能（Δ Gc：），结果表明，CD 2Cl 2对二苯基和二叔丁基取代的冠醚具有高度的手性识别作用.二苯基和二叔丁基取代的冠醚在甲醇和甲醇-氯仿混合物中对NapEt和其他手性有机铵盐的对映体也表现出很高的手性识别，如通过直接1H NMR技术测定的log K值的较大差异所示
Three new chiral pyridino-18-crown-6 ligands have been prepared. These ligands contain either two phenyl, two tert-butyl, or two methyl substituents on chiral macroring carbon atoms. The chiral di-tert-butyl-substituted diester crown analogue was also prepared. The starting chiral di-tert-butyl-substituted tetraethylene glycol needed to prepare the two di-tert-butyl-substituted crowns was obtained from chiral tert-butyl-1,2-ethanediol, which was resolved from its bis(hydrogen phthalate) brucine salt. A high degree of chiral recognition of CD 2 Cl 2 of the enantiomers of [α-(1-naphthyl)ethyl] ammonium perchlorate (NapEt) was shown by the diphenyl- and di-tert-butyl-substituted crowns by differences in the free energy of activation (ΔG c : ) values determined by temperature-dependent i H NMR spectroscopy. The diphenyl- and di-tert-butyl-substituted crowns also exhibited high chiral recognition for the enantiomers of NapEt and other chiral organic ammonium salts in methanol and methanol-chloroform mixtures as shown by a large difference in the log K values determined by a direct i H NMR technique