Efficient Synthesis of a Bisglycosyl Kaempferol from Fagonia taeckholmiana

The first total synthesis of kaempferol-3-O-beta-L-arabinopyranosyl-(1 -> 4)-alpha-L-rhamnopyranoside-7-O-alpha-L-rhamnopyranoside (1), a 3,7-triglycosylflavone, which was isolated from the aerial parts of Fagonia taeckholmiana, was accomplished in 13 steps and 9.2% overall yield from commercially available kaempferol. We efficiently employed phase-transfer-catalyzed (PTC) glycosylation for the construction of phenol glycosides. Applying this approach will allow the preparation of derivatives for further study of structure-activity relationships (SAR).