Thestereochemistryoftwo6,9-oxygenbridgedibenzocyclooctadienelignansfromKadsuracoccinea,aredifficulttoseparateandveryunstable.Thepresentstudywasdesignedtodevelopahigh-performanceliquidchromatographyusingcirculardichroismdetectionfortheanalysisofthestereochemistry.Anew6,9-oxygenbridgedibenzocyclooctadienelignansnamedKadsulignanQwasfirstlyfoundwithanS-biphenylconfiguration.TheothercompoundwasidentifiedasKadsulignanLwithanR-biphenylconfiguration.Inordertoobtainkineticdataontheirreversibleinterconversion,thestabilitywasmeasuredatdifferentdeuteratedsolventssuchasdeuteratedmethanol,deuteratedchloroformanddeuterateddimethylsulfoxide.Thelignansweremoreunstableandconvertedmoreeasilyindeuteratedmethanolthanindeuteratedchloroformanddeuterateddimethylsulfoxide.