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Study on The Generation of Reactive Intermediates through Thermal Hydrogen Shift and Their Application to Selective Heterocycle Synthesis

热氢变换生成反应中间体及其在选择性杂环合成中的应用研究

基本信息

批准号：
13650905
负责人：
NOGUCHI Michihiko
金额：
$ 2.3万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

In order to apply the 1,3-dipolar intermediates generated by thermal hydrogen shift of oximes and hydrazones to heterocycles synthesis, investigations on the hydrogen shift process were done. The resultant N-unsubstituted 1,3-dipoles were stabilizing by forming an hydrogen bond between the NH of the dipoles and the carbonyl oxygen located in the same molecule. Consequently, an increase of the concentration of the dipoles should be allowed to apply the dipoles to intermolecular cycloaddition reactions with dipolarophiles, which were found in few literatures. Although the reaction of the heterocyclic aldehyde oximes provided the second example for the intermolecular cycloaddition of NH-nitrone, maleimides were limited as a dipolarophile.The facile hydrazone-azomethine imine isomerization in the system was accomplished and the intermolecular cycloaddtion of the resultant dipole with olefinic dipolarophiles to afford cycloadducts efficiently and stereoselectively. The acid treatment of the … More cycloadducts caused the fission of the heterocyclic moiety to afford 2-pyrroline derivatives, which were also considered as cycloadducts of a C-unsubstituted nitrile imine and the olefinic dipolarophiles. Since only few papers on C-unsubstituted nitrile imines were found, it is very interesting from a synthetic point of view to consider these results as an equivalent reaction to C-unsubstituted nitrile imines' one.The thermal reaction of N-phenyl imines of the heterocyclic aldehyde bearing amino acid ester moieties at the adjacent position gave 2-pyrroline derivatives fused by the heterocyclic system, in which the 1,5-electrocyclic ring-closure of the α,β-unsaturated azomethine ylides generated by thermal 1,6-hydrogen shift of the imines. The relative configuration between the anilino group and the ester moiety depended on the structure of the amino acid esters; a cis configuration for acyclic amino acid esters and a trans one for cyclic amino acid esters. The discrepancy of the configuration is explained by the steric interaction in the transition state geometries of the cyclization process.As mentioned above, these synthetic reactions were performed by a simple procedure, only "heating", and afforded many heterocycles efficientiy and stereoselectively. I think that I have proposed a novel synthetic methodology matching to ecological and environmental points. Less

为了将肟和腙的热氢移反应生成的1，3-偶极中间体应用于杂环化合物的合成，对氢移反应过程进行了研究。得到的N-未取代的1，3-偶极通过在偶极的NH和位于同一分子中的羰基氧之间形成氢键而稳定。因此，应允许增加偶极的浓度，以将偶极应用于与亲偶极试剂的分子间环加成反应，这在文献中很少发现。虽然杂环醛肟的反应提供了NH-硝酮分子间环加成反应的第二个例子，但马来酰亚胺仅限于亲偶极试剂，在该体系中实现了易于实现的腙-甲亚胺异构化，并使生成的偶极试剂与烯属亲偶极试剂有效地立体选择性地进行了分子间环加成反应。的酸处理 ...更多信息环加合物引起杂环部分的分裂，得到2-吡咯啉衍生物，其也被认为是C-未取代的腈亚胺和烯属亲偶极试剂的环加合物。由于C-未取代腈亚胺的文献很少，从合成的观点来看，将这些结果视为与C-未取代腈亚胺反应的等价反应是非常有趣的.在相邻位置带有氨基酸酯部分的杂环醛的N-苯基亚胺的热反应得到了由杂环系统稠合的2-吡咯啉衍生物，其中1，通过亚胺的热1，6-氢移位产生的α，β-不饱和甲亚胺叶立德的5-电环闭环。苯胺基和酯基之间的相对构型取决于氨基酸酯的结构;非环状氨基酸酯为顺式构型，环状氨基酸酯为反式构型。构型的差异可以用环化反应过渡态几何构型中的空间相互作用来解释.如上所述，这些合成反应都是通过简单的“加热”过程来完成的，并且高效、立体选择性地得到了许多杂环化合物.我认为，我提出了一种新的综合方法，符合生态和环境的观点。少