Glycals in the stereoselective synthesis of triterpene 2-deoxy-alpha-L-glycosides under conditions of acidic catalysis.
3beta-Hydroxy triterpenes of the oleanane, ursane, and lupane types were successfully glycosylated with acetylated L-glucal and L-rhamnal under conditions of acidic catalysis (anhydrous cation-exchange resin and LiBr). The 2-deoxy- and 2, 6-dideoxy-alpha-L-arabino-hexopyranosides (1-5) were stereoselectively prepared in 83-90% yields, following deacetylation under mild conditions, which led to the target triterpene 2-deoxy-alpha-L-glycosides (6-10).
Institute of Organic Chemistry, Ufa Research Center of the Russian Academy of Sciences, 71 Prospect Oktyabrya, 450054 Ufa, Russian Federation. chemlum@ufanet.ru
O B
OB
Flekhter
L A
LA
Baltina
G A
GA
Tolstikov
D000143:Acids / Q000737:chemistry; D002384:Catalysis; D006027:Glycosides / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D014315:Triterpenes / Q000737:chemistry*
D000143:Acids; D006027:Glycosides; D014315:Triterpenes