Submitted to: Current Organic Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2009
Publication Date: 1/19/2010
Citation: Li, X., Ferreria, D., Ding, Y. 2010. Determination of absolute configuration of natural products: theoretical calculation of electronic circular dichroism as a tool. Current Organic Chemistry. 14:1678-1697. Interpretive Summary: This manuscript reviews recent advancements on the application of the time dependent density functional theory to the calculation of electronic circular dichroism of natural products for absolute configuration assignment.
Technical Abstract: Determination of absolute configuration (AC) is one of the most challenging features in the structure elucidation of chiral natural products, especially those with complex structures. With revolutionary advancements in the area of quantum chemical calculations of chiroptical spectroscopy over the past decade, the time dependent density functional theory (TDDFT) calculation of electronic circular dichroism (ECD) spectra has emerged as a very promising tool. The principle is simply based on the comparison of the calculated and experimental ECD spectra: the more closely they match, the more reliable conclusion for the AC assignment can be drawn. This review attempts to use several examples representing monomeric flavonoids, rotationally restricted biflavonoids, complex hexahydroxydiphenoyl-containing flavonoids, conformationally flexible and restrained sesquiterpenoids, cembrane-africanene terpenoids, dihydropyranocoumarins, alkaloids and dihydroxanthones to illustrate the applicability of this approach in determining the AC of structurally diverse natural products. The findings clearly indicate that the TDDFT calculation of ECD spectra can quantify the contribution of individual conformers and the interaction of multiple chromophores, making it possible to determine the AC of complex chiral molecules. The calculated electronic transitions and molecular orbitals provide new insight into the interpretation of ECD spectra at the molecular level.