Biosynthesis of the brevianamides. An ab initio study of the biosynthetic intramolecular Diels-Alder cycloaddition
Biosynthesis of the brevianamides. An ab initio study of the biosynthetic intramolecular Diels-Alder cycloaddition
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DOI：
10.1021/jo9621783
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发表时间：
1997-03-21
影响因子：
3.6
通讯作者：
Marco, JA
中科院分区：
文献类型：
--
作者：
Domingo, LR;SanzCervera, JF;Marco, JA
采用Hartree-Fock方法，在从头算3 - 21 G和6 - 31 G~*基组下，对氮杂二烯6分子内Diels-Alder环加成反应生成灯盏花素酰胺A，1和B，2的过渡结构进行了从头算研究.在MP2和MP3水平上用微扰方法估计了关联效应。几何构型、电子结构和跃迁矢量分量定性地与模型无关。对相应过渡结构的几何形状和能量的分析提供了对以下事实的解释：短藤胺A（1）的生物合成量大于短藤胺B（2），而它们各自在C7处的差向异构体没有形成。
An ab initio study of the transition structures for the intramolecular Diels-Alder cycloaddition of the aza diene 6 to give brevianamides A, 1, and B, 2, has been carried out with analytical gradients at ab initio 3-21G and 6-31G* basis sets within Hartree-Fock procedures. The correlation effects have been estimated by using the perturbational approach at MP2 and MP3 levels, The geometry, electronic structure, and transition vector component are qualitatively model independent in this study. An analysis of the geometries and energies of the corresponding transition structures provides an explanation for the fact that brevianamide A, 1, is biosynthesized in larger quantities than brevianamide B, 2, while their respective epimers at C7 are not formed.