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Four interesting sequoiatones stereoisomers(1-4) were isolated from a wetland soil-derived fungus Talaromyces flavus by 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,1 and 3(or 2 and 4)were a pair of enantiomers,and 1 and 2(or 3 and 4) 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 1-4 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.
Four interesting sequoiatones stereoisomers (1-4) were isolated from a wetland soil-derived fungus Talaromyces flavus by chiral HPLC. On the basis of comprehensive NMR and mass analyzes, their planar structures were elucidated as the same as that of sequoiatone B.Among them , 1 and 3 (or 2 and 4) were a pair of enantiomers, and 1 and 2 (or 3 and 4) were a pair of stereoisomers with epimerization at C-12, which indicates that sequoiation-type metabolites exist as enantiomers rather than the absolute configurations of C-8 in 1-4 were determined, which is the first report to establish the absolute configuration of C-8 in sequoiatones. Despite, the absolute configurations of C-12 in sequoiatones are still unsolved.