A set of interesting sequoiatones stereoisomers from a wetland soil-derived fungus

ABSTRACT

Four interesting sequoiatones stereoisomers (-) were isolated from a wetland soil-derived fungusby chiral HPLC. On the basis of comprehensive NMR and mass analyses, their planar structures were elucidated as the same as that of sequoiatone B. Among them,and(orand) were a pair of enantiomers, andand(orand) were a pair of stereoisomers with epimerization at C-12, which indicated that sequoiatione-type metabolites exist as enantiomers rather than as optically pure compounds in some strains. With the quantum chemical ECD calculations, the absolute configurations of C-8 in-were determined, which is the first report to establish the absolute configuration of C-8 in sequoiatones. However, the absolute configurations of C-12 in sequoiatones are still unsolved.