Absolute Configurations of Fungal and Plant Metabolites by Chiroptical Methods. ORD, ECD, and VCD Studies on Phyllostin, Scytolide, and Oxysporone

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• 作者：Giuseppe Mazzeo ; Ernesto Santoro ; Anna Andolfi ; Alessio Cimmino ; Pavle Troselj ; Ana G. Petrovic ; Stefano Superchi ; Antonio Evidente ; Nina Berova
• 刊名：Journal of Natural Products
• 出版年：2013
• 出版时间：April 26, 2013
• 年：2013
• 卷：76
• 期：4
• 页码：588-599
• 全文大小：593K
• 年卷期：v.76,no.4(April 26, 2013)
• ISSN：1520-6025

文摘

The absolute configuration (AC) of the bioactive metabolites phyllostin (1) and scytolide (2), two hexahydro-1,4-benzodioxines produced by Phyllosticta cirsii, and oxysporone (3), a dihydrofuropyranone recently isolated from a strain of Diplodia africana, has been assigned by computational analysis of their optical rotatory dispersion (ORD), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) spectra. Computational prediction of ORD, ECD, and VCD allowed us to assign (3S,4aR,8S,8aR) AC to naturally occurring (鈭?-1, while (4aR,8S,8aR) AC was assigned to (鈭?-2 employing only ECD and VCD, because in this case ORD analysis turned out to be unsuitable for AC assignment. Theoretical prediction of both ORD and ECD spectra of 3 led to assignment of (4S,5R,6R) AC to (+)-3. In this case a satisfactory agreement between experimental and calculated VCD spectra was obtained only after taking into account solvent effects. This study shows that in the case of flexible and complex natural products only a concerted application of more than a single chiroptical technique permits unambiguous assignment of absolute configuration.