Regiolone and isosclerone, two enantiomeric phytotoxic naphthalenone pentaketides: Computational assignment of absolute configuration and its relationship with phytotoxic activity

The absolute configurations of regiolone and isosclerone, two enantiomeric bioactive naphthalenone pentaketides produced by fungi and plants, have been unambiguously assigned by ab initio computational prediction of their theoretical optical rotatory powers and electronic circular dichroism spectra. Isosclerone is produced by the plant pathogen Botrytis cinerea, whereas regiolone is produced by B. fabae. The phytotoxic activities of the two compounds were tested for comparison on faba bean (host of both pathogens) and vine plants (host of only B. cinerea); the (R) configuration at C-4 was found to be a fundamental structural feature for bioactivity. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
This work was supported in part by the Spanish Ministry of Science and Innovation (project AGL2008-02139) and in part by a grant from the Università della Basilicata (Potenza) and the Ministry of University and Research (Rome) (project PRIN2008, “Determination of the molecular absolute configuration by means of chiroptical spectroscopy: development of new efficient methods and their application to bioactive molecules”). A grant to A. C. was funded by the Spanish Juan de la Cierva program (contribution DISSPAPA247).