Enantiomeric Dibenzo-α-Pyrone Derivatives from ZHJG5 and Their Potential as Agrochemicals.

Three pairs of enantiomeric dibenzo-α-pyrone derivatives (-) including two pairs of new racemates (±)-alternaone A () and (±)-alternaone B () and one new enantiomer (-)-alternatiol (), together with five known compounds (-) were isolated from the fungus ZHJG5. Their structures were confirmed by spectroscopic data and single-crystal X-ray diffraction analysis. All enantiomers were separated via chiral high-performance liquid chromatography, with their configurations determined by electronic circular dichroism calculation. Biogenetically, a key epoxy-rearrangement step was proposed for the formation of skeletons in -; (+) , (-)-, and presented moderate antibacterial inhibition on phytopathogenic bacteria pv. and pv. . In the antifungal test, compounds and showed a moderate protective effect against in vivo.