Stereochemical determination of acyclic structures based on carbon-proton spin-coupling constants. A method of configuration analysis for natural products
Stereochemical determination of acyclic structures based on carbon-proton spin-coupling constants. A method of configuration analysis for natural products
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DOI：
10.1021/jo981810k
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发表时间：
1999-02-05
影响因子：
3.6
通讯作者：
Tachibana, K
中科院分区：
文献类型：
--
作者：
Matsumori, N;Kaneno, D;Tachibana, K
本文提出了一种基于碳-质子自旋偶合常数（（2，3）J（C，H））和质子间自旋偶合常数（（3）J（H，H））的非环状有机化合物相对构型解析方法。该方法基于以下理论：在无环体系中，相邻不对称中心的构象由交错旋转异构体表示，并且它们的相对立体化学可以使用（2，3）J（C，H）和（3）J（H，H）来确定，因为这些J值的组合使用使得能够从源自苏式和双反式构型的六种可能构型中鉴定出主要交错旋转异构体。模型化合物1-4的详细构象分析表明，这种方法是有用的，在大多数情况下，在天然产物中发生的非环状结构的配置，其中立体异构次甲基碳经常被取代的甲基或羟基（烷氧基）基团的归属。这种基于J的构型分析被应用于虫黄毒素衍生的羧酸5的立体化学解析，并被证明是一种实用的方法，即使是具有复杂结构的天然产物。
A method for elucidating the relative configuration of acyclic organic compounds was developed on the basis of carbon-proton spin-coupling constants ((2,3)J(C,H)) and interproton spin-coupling constants ((3)J(H,H)). This method is based on the theory that, in acyclic systems, the conformation of adjacent asymmetric centers is represented by staggered rotamers, and their relative stereochemistry can be determined using (2,3)J(C,H) and (3)J(H,H), because the combined use of these J values enables the identification of the predominant staggered rotamer(s) out of the six possible derived from threo and erythro configurations. Detailed conformational analysis for model compounds 1-4 revealed that this method is useful in most cases for assignment of the configuration of acyclic structures occurring in natural products, in which stereogenic methine carbons are often substituted with a methyl or a hydroxy (alkoxy) group. This J-based configuration analysis was applied to the stereochemical elucidation of carboxylic acid 5 derived from zooxanthellatoxin and proven to be a practical method even for natural products with complicated structures.