title: A modular approach to aryl-C-ribonucleosides via the allylic substitution and ring-closing metathesis sequence. a stereocontrolled synthesis of all four α-/β- and D-/L-C-nucleoside stereoisomers.
abstract: Iridium(I)-catalyzed allylation of the enantiopure monoprotected copper(I) alkoxide, generated from (S)-5a, with the enantiopure allylic carbonates (R)-9a,b has been developed as the key step in a new approach to C-nucleoside analogues. The anomeric center was thus constructed via a stereocontrolled formation of the C-O rather than C-C bond with retention of configuration. The resulting bisallyl ethers 15a,b (≥90% de and >99% ee) were converted into C-ribosides 29a,b via the Ru-catalyzed ring-closing metathesis, followed by a diastereoselective dihydroxylation catalyzed by OsO(4) or RuO(4) and deprotection. Variation of the absolute configuration of the starting segments 5a and 9a,b allowed a stereocontrolled synthesis of all four α/β-D/L-combinations.
authors.affiliation: Department of Chemistry, WestChem, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
authors.forename: Jan
authors.initials: J
authors.lastname: Štambaský
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Kapras
authors.forename: Martin
authors.initials: M
authors.lastname: Štefko
authors.forename: Ondřej
authors.initials: O
authors.lastname: Kysilka
authors.forename: Michal
authors.initials: M
authors.lastname: Hocek
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Malkov
authors.forename: Pavel
authors.initials: P
authors.lastname: Kočovský
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D006900:Hydroxylation; D007495:Iridium / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry; D012263:Ribonucleosides / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000475:Alkenes; D002254:Carbonates; D012263:Ribonucleosides; D007495:Iridium; D012238:Rhodium; D010100:Oxygen