The electronic circular dichroism (ECD) spectra of two sesquiterpenoids (1 and 2) related to oplopanone, obtained from a methanolic extract of the plant Serphidium stenocephalum (Artemisia stenocephala), were measured and reproduced by means of time-dependent density functional theory (TDDFT) calculations, establishing their absolute configuration. The application of ketone octant rule for carbonyl n-* ECD band to compounds 1 and 2, which include an acyclic carbonyl group, was critically assessed. The peculiar oplopanone skeleton makes a straightforward application of the octant rule impossible, because of the uncertainty related to the shape of the so-called third nodal surface separating front and back octants. The various group contributions to the carbonyl n-* ECD band were estimated with TDDFT calculations on selected molecular models obtained by consecutive dissections from 1. Chirality 26:39-43, 2013. (c) 2013 Wiley Periodicals, Inc.
|Autori interni:||PESCITELLI, GENNARO|
|Autori:||N. Shafiq;M. Saleem;N. Riaz;M. I. Tousif;A. Jabbar;R. B. Tareen;G. Pescitelli|
|Titolo:||Absolute Configuration of Oplopanone Derivatives From Serphidium stenocephalum: ECD Spectra of Acyclic Ketones With Front-Octant Contributions|
|Anno del prodotto:||2014|
|Digital Object Identifier (DOI):||10.1002/chir.22263|
|Appare nelle tipologie:||1.1 Articolo in rivista|