Determining the stereochemistry of molecules from residual dipolar couplings (RDCs)

Abstract

Residual dipolar couplings (RDCs) have recently revolutionized the structure determination of biological macromolecules by NMR spectroscopy. Their utility in the structure determination of small/medium-sized organic compounds is more and more recognized. The questions arising in organic compounds are completely different from biomolecular NMR. Especially, the determination of the stereochemistry (relative configuration and diastereotopic assignments) is the focus of this article. A short overview on how to introduce the anisotropic environment necessary to measure RDCs and the applications for the determination of relative configurations in rigid and moderately flexible compounds are given together with the description of the theoretical background for interpreting the data. Since the area of alignment media for organic compounds and the applications to flexible compounds are developing extremely fast, this article can be viewed as momentary picture only.