De novo asymmetric syntheses of SL0101 and its analogues via a palladium-catalyzed glycosylation.
The enantioselective syntheses of naturally occurring kaempferol glycoside SL0101 (1a) and its analogues 1b-e, as well as their enantiomers, have been achieved in 7-10 steps. The routes rely upon a diastereoselective palladium-catalyzed 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 an acylfuran. An acetyl group shift from an axial (C-2) to equatorial position (C-3) under basic conditions was also described. [reaction: see text]
Shan
Mingde
M
Department of Chemistry, West Virginia University, Morgantown, WV 26506, USA.
O'Doherty
George A
GA
D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D006031:Glycosylation; D015394:Molecular Structure; D009005:Monosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
D001578:Benzopyrans; D009005:Monosaccharides; C497449:SL0101; D010165:Palladium