State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, China.
Chin J Nat Med. 2013 May;11(3):193-8. doi: 10.1016/S1875-5364(13)60016-3.
Structural elucidation of natural products is always one of the most important tasks for natural product researchers in related fields. Particularly, the absolute configuration (AC), being a great challenge for natural product chemists, has attracted much attention. During the past few decades, many techniques and approaches have been developed to determine the AC of natural products, including direct (or absolute) methods, e.g. X-ray diffraction (XRD), electronic and vibrational circular dichroism (ECD and VCD), and Raman optical activity (ROA), as well as indirect (or relative) methods using a reference or a derivatizing agent with known AC, e.g. CD with empirical rules and nuclear magnetic resonance (NMR) utilizing anisotropic effects of chiral derivatizing agents. However, none of the currently applied techniques is capable of dominating AC determination, since they each have their respective limitations corresponding to the different structural features. This mini review summarizes most of the techniques and methods which are commonly used in AC assignment of natural products, or have potential application prospects, and briefly describes their principles, advantages and limitations.
天然产物的结构解析一直是相关领域天然产物研究人员的最重要任务之一。特别是，绝对构型（AC）是天然产物化学家面临的巨大挑战，引起了广泛关注。在过去的几十年中，已经开发出许多技术和方法来确定天然产物的 AC，包括直接（或绝对）方法，例如 X 射线衍射（XRD）、电子和振动圆二色性（ECD 和 VCD）和拉曼旋光活性（ROA），以及使用具有已知 AC 的参考物或衍生化试剂的间接（或相对）方法，例如具有经验规则的 CD 和利用手性衍生化试剂各向异性效应的核磁共振（NMR）。然而，目前应用的技术都不能主导 AC 测定，因为它们各自对应于不同的结构特征都有其各自的局限性。这篇综述总结了常用于天然产物 AC 分配的大多数技术和方法，或具有潜在应用前景，并简要描述了它们的原理、优点和局限性。
