In Depth Analysis of Chiroptical Properties of Enones Derived from Abietic Acid.
J Org Chem
; 83(7): 3547-3561, 2018 04 06.
Article
en En
| MEDLINE
| ID: mdl-29490457
With the use of inexpensive commercially available abietic acid, a whole series of abietane enones were prepared in high yields. The structures of all the products obtained were determined by comprehensive spectroscopic analysis with particular emphasis on the use of advanced NMR techniques, comparison with previously reported data and, where possible, by single crystal X-ray diffraction. However, in cases where X-ray crystallography was not applicable or compounds tested were unstable, a final stereochemical assignment could be inferred only by electronic circular dichroism (ECD) supported by vibrational circular dichroism to increase credibility. To reveal the relationship between structure and chiroptical properties, we used combined experimental and theoretical analysis of geometries, structural parameters, and chiroptical properties of all enones synthesized. A thorough analysis of their conformational flexibility by examining the effect of solvent and temperature on the ECD spectra was also used to achieve desired objectives. As a result, the impact of substituents adjacent to the enone chromophore on the conformation was determined by demonstrating that even slight changes in the position of hydroxyl and isopropyl groups attached to carbon C13 may substantially affect ECD curves' pattern, leading in some cases to Cotton effects sign reversal.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Org Chem
Año:
2018
Tipo del documento:
Article
País de afiliación:
Polonia
Pais de publicación:
Estados Unidos