Regiolone and Isosclerone, Two Enantiomeric Phytotoxic Naphthalenone Pentaketides: Computational Assignment of Absolute Configuration and Its Relationship with Phytotoxic Activity

Abstract

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

Synthesis and L-type calcium channel blocking activity of new chiral oxadiazolothiazinones

“…S7 in the Supplementary Data). ECD spectra for each conformer were calculated using TDDFT at the CAM-B3LYP/aug-cc-pVDZ level [16,17] and Boltzmann averaged obtaining the weighted spectrum shown in Fig. 3.…”

The Effect of Stereochemistry on the Biological Activity of Natural Phytotoxins, Fungicides, Insecticides and Herbicides

“…However, it has been mistakenly called (–)‐isosclerone and in other cases it was isolated together with isosclerone as racemate. Isosclerone (+)‐7 , as mentioned above, has been isolated from pathogenic fungi of different crops, but has also been isolated as an antitumor metabolite and plant metabolite …”

A pair of new tetrahydro-naphthalenone enantiomers from Eremurus altaicus (Pall.) Stev.

“…The stereochemistry of tetralone derivatives has been well investigated by computational approaches (Bringmann et al, 2001;Evidente et al, 2011;Sun et al, 2013), and the absolute configurations of regiolone and isosclerone have been clearly determined by Evidente on the basis of the comparison of simulated OR values and ECD spectra using the time-dependant density functional theory (TDDFT) method with the experimental spectra . Thus, the assignment of the absolute configurations of 1a and 1b was conducted by ECD spectroscopy in combination with the quantum-chemical calculations in a similar manner.…”