Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations
Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations
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DOI：
10.3390/md12074031
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发表时间：
2014-07-01
期刊：
影响因子：
5.4
通讯作者：
Souto, Maria L.
中科院分区：
文献类型：
--
作者：
Gutierrez-Cepeda, Adrian;Hernandez Daranas, Antonio;Souto, Maria L.
五元环特别令人感兴趣，因为它们存在于化学和生物学中一些最常见的分子中。尽管它们表面上很简单，但由于它们固有的构象灵活性，这些环的结构解析很复杂。在这里，我们描述了最近报道的基于自旋-自旋耦合常数测量的简单有效的 NMR 协议的应用，以实现从红藻 Laurencia marilzae 中分离出的五种新型卤化 C-15 四氢呋喃基-acetogenins、marilzafurolenes A-D (1-4) 和 12-acetoxy-marilzafurenyne (5) 的具有挑战性的相对构型。尽管 DFT 化学位移计算用于连接远程立构中心，但在这种情况下基于 NMR 的方法似乎比计算技术更有优势，因为卤素的存在可能会干扰可靠的计算。
Five-membered rings are of particular interest, due to their presence in some of the most common molecules in chemistry and biology. Despite their apparent simplicity, the structural resolution of these rings is complex, due to their inherent conformational flexibility. Here, we describe an application of a recently reported simple and efficient NMR protocol based on the measurement of spin-spin coupling constants to achieve the challenging relative configurations of five new halogenated C-15 tetrahydrofuranyl-acetogenins, marilzafurollenes A-D (1-4) and 12-acetoxy-marilzafurenyne (5), isolated from the red alga, Laurencia marilzae. Although DFT chemical shift calculations were used to connect remote stereocenters, the NMR-based approach seems advantageous over computational techniques in this context, as the presence of halogens may interfere with reliable calculations.