De novo asymmetric syntheses and biological evaluation of SL0101 and its enantiomer via a palladium-catalyzed glycosylation

ORGN 676

Bulan Wu, bulanwu101@yahoo.com, Department of Chemistry, West Virginia University, Morgantown, WV 26506 and George A. O'Doherty, george.odoherty@mail.wvu.edu, C. Eugene Bennett Department of Chemistry, West Virginia University, 284 Prospect Street, 217 Clark Hall of Chemistry, WVU, Morgantown, WV 26506-6045.
The enantioselective syntheses of naturally occurring kaempferol glycoside SL0101 and its analogues, as well as their enantiomers, have been achieved in 7-10 steps. The routes rely upon a diastereoselective palladium-catalysed glycosylation, ketone reduction, and dihydroxylation to introduce the rhamno-stereochemistry. The asymmetry of the sugar moiety of these kaempferol glycosides was derived from Noyori reduction of a furanketone. An acetyl group shift from an axial (C-2) to equatorial position (C-3) under basic conditions was also described.