Revising the Absolute Configurations of Coatlines via Density Functional Theory Calculations of Electronic Circular Dichroism Spectra

Abstract

Coatline A (1) and α-epi-coatline A (4) co-occur in the trunk extract of Andira coriacea. Inspection of their chiroptical properties led to intriguing results. After a careful examination of the experimental data used for the previously reported absolute configuration of these compounds, some uncertainties were identified. A combined theoretical approach including conformational analyses and calculation of electronic circular dichroism (ECD) spectra, in addition with experimental data obtained for schoepfin A (5) and the new schoepfin D (6) isolated from Senna quinquangulata, allowed the revision of the absolute configuration of coatlines A (1) and B (2).