Relative and absolute configurations of dissolved molecules by NMR-spectroscopy in orienting media

该研究单位（DFG-Forschergruppe）的目的是开发一种普遍适用的通用方法，用于计算机辅助核磁共振光谱测定天然产物和其他有机化合物的相对和绝对构型，该方法基于各向异性核磁共振参数（残余偶极耦合、rdc和残余化学位移各向异性）。RCSA)以及相对构型和绝对构型的非手性取向介质和手性取向介质的开发与应用。多年来，NOE或3J标量偶联常数等参数已被应用于溶解分子的构象分析，在大多数情况下，这些分子是具有明确立体中心的生物聚合物。由于任意化合物的j偶联缺乏参数化，因此迫切需要应用不受此限制的额外结构约束，例如RDC的结构约束。此外，与基于NOE/ j耦合的结构解析不同，RDC对标量或NOE连通性的中断不敏感。这在未知立体单元的构型分配的背景下是特别重要的，特别是当它们彼此相距很远的时候。为了实现这一目标并满足对多对准数据集的需求，必须开发新的对准介质（非手性和手性）以及测量、解释和预测RDC的新方法。在下文中，将简要描述研究单位在这些目标方面的进展。在此基础上，对未来的研究方向进行了探讨。结果将在第2节和各自的提案中进行简要描述。

The aim of this research unit (DFG-Forschergruppe) is the development of a generally applicable and versatile method for the computer-assisted NMR-spectroscopic determination of the relative and absolute configuration of natural products and other organic compounds based on anisotropic NMR-parameters (residual dipolar couplings, RDCs and residual chemical shift anisotropy, RCSA) and the development and application of achiral and chiral orienting media for the relative and absolute configuration, respectively. Since many years parameters like the NOE or the 3J scalar coupling constants have been applied for the conformational analysis of dissolved molecules being biopolymers with defined stereogenic centers in most cases. Due to the lacking parametrization of J-couplings for arbitray compounds, the application of additional structural restraints without this limitation, such as RDC's, is an urgent necessity. Moreover, unlike the NOE/J-coupling based structural elucidation, RDC's are not sensitive to breaks in the scalar or NOE connectivities. This is of special importance in the context of configurational assignments of unknown stereogenic units, particularly if they are far away from each other. To achieve this goal and to meet the need for multiple-alignment data sets, new alignment media (achiral and chiral) as well as new methods for the measurement, interpretation and prediction of RDC's have to be developed. In the following, the progress of the research unit with respect to these goals will be described briefly. After this survey the future research directions will be discussed. Results are described briefly in section 2 and in the individual proposals in their native context.