Minimizing the risk of deducing wrong natural product structures from NMR data

• Published in: Magnetic resonance in chemistry Vol. 59; no. 5; pp. 500 - 533
• Main Authors: Burns, Darcy C., Reynolds, William F.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.05.2021
• Subjects: 1,1‐ADEQUATE; Chemists; COSY; HMBC; Natural products; NMR; NOESY; Nuclear magnetic resonance; structure elucidation; Training; natural products; 1,1-ADEQUATE; HMBC; NOESY; structure elucidation; COSY; CASE
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.4933

There continues to be a disturbing number of natural products reported in the literature whose structures are incorrect. At least in part, this reflects the fact that many natural product chemists have limited formal nuclear magnetic resonance training. Gaps in training and lack of awareness regarding the challenges and ambiguities associated with two‐dimensional nuclear magnetic resonance data interpretation can easily lead to errors in structure elucidation. The purpose of this tutorial is to point out some of these issues, highlight the kinds of errors that have been made and provide specific advice on how to avoid these missteps such that the risk of reporting a wrong structure is minimized. There have been many incorrect natural product structures that have been predicted from NMR data and many different reasons why the errors were made. These include predicting structures from incomplete data, ignoring data that are inconsistent with a predicted structure, using 2D NMR data of inadequate quality, ignoring ambiguities when interpreting HMBC data, and failing to recognize that more than one structure may be consistent with the data. Ways to minimize the risks of making these errors are provided.