Reinvestigation of Absolute Stereostructure of (−)-Rosiridol: Structures of Monoterpene Glycosides, Rosiridin, Rosiridosides A, B, and C, from Rhodiola sachalinensis

Abstract

Three new (−)-rosiridol glycosides, rosiridosides A, B, and C, were isolated from the roots of Rhodiola sachalinensis together with rosiridin [(−)-rosiridol 1-O-β-D-glucopyranoside]. In the course of the structure elucidation of those new glycosides, the absolute configuration of the 4-position in (−)-rosiridol was reinvestigated. On the basis of the application of the modified Mosher's method for (−)- and (+)-rosiridol derivatives, the absolute configuration of the 4-position in (−)-rosiridol should be revised to be S orientation from the recently assigned R form, so that the absolute stereostructures of rosiridosides A, B, and C and rosiridin were determined.