We present a method to use long-range CH coupling constants to derive the correct diastereoisomer from the molecular constitution of small molecules. A set of 79 J and J values collected from a single HSQMBC experiment on a sample of strychnine were used in the CASE-3D (computer-assisted 3D structure elucidation) protocol. In addition to the most commonly used J coupling constants, the subset of 32 J values alone showed an excellent degree of configuration selection. The study is mainly based on comparison of DFT-calculated J values with experimental ones, critical for the case of J . But the configuration selection also works well using J values predicted from a semi-empirical Karplus-based equation limited to H-C-C-C fragments. The robustness, shown using strychnine as a proof of concept, makes the J-based CASE-3D analysis a viable option for the application in fields such as peptide and carbohydrate research, organic synthesis, natural-product identification and analysis, as well as medicinal chemistry.
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