偶合常数分析在柔性天然分子相对构型鉴定中的应用

Application of coupling constant based analysis in determining the relative configuration of flexible natural molecules

天然产物中的柔性结构片段可自由旋转,其相对构型的确定仍然具有相当的挑战性。基于偶合常数的构型分析方法(JBCA)可有效地解决该类问题。该法主要应用于邻/间二次甲基柔性结构片段,结合氢-氢和碳-氢偶合常数(3JH,H,2,3JH,C)以及核欧沃豪斯效应(NOE)测试对柔性结构片段进行构象分析,进而确定其相对构型。本文简要综述了该法近年来在柔性天然分子结构鉴定中的研究进展,希望为天然产物立体化学研究提供一定参考。

The determination of the relative configuration of fiexible natural molecules is still a challenge due to the geometrical uncertainty of their flexible moieties. Coupling constant based configuration analysis（JBCA） is a valid approach in elucidating the relative configuration of these flexible systems. The approach is suitable for 1,2- or 1,3-dimethine systems. The final relative configuration assignment on chiral organic compounds stems from conformational analysis by combining proton-proton and/or proton-carbon coupling values and nuclear overhauser effect（NOE） correlations. This paper gives a brief review on the latest application of coupling constant based analysis in determining the relative configuration of flexible natural molecules,aiming to give a reference to natural product research regarding the stereochemistry.