Structural Revisions of Natural Products with the Aid of the Structure Elucidator System

Abstract

Every year a number of articles are published that contain incorrectly elucidated structures. Based on our experience with the application of CASE systems it is expected that such software and algorithms can help the chemist in the elucidation process or can at least provide warnings for structures suggested by scientists. This chapter therefore reviews the application of CASE to a series of examples for which the original structures were later revised. It is demonstrated that the chemical structure can be correctly elucidated if 2D NMR data were available and the expert system Structure Elucidator is employed. It is also shown that if only 1D NMR spectra from the original articles were used then simply the calculation of the 13C chemical shifts for the hypothetical structures frequently allows a scientist to realize that the structural hypothesis is likely incorrect.