title: Studies on 2'-alpha-C-carboxyalkyl nucleosides and their application to a stereocontrolled nucleobase exchange process.
abstract: The ability of 2'-alpha-C-carboxyalkyl nucleosides to undergo an unusual two-step stereocontrolled nucleobase exchange process has been investigated. Upon silylation a protected 2'-deoxy-2'-alpha-C-(carboxymethyl)uridine derivative can undergo intramolecular displacement of the uracil base, by the 2'-carboxylic acid group, to form a pentofuranosyl gamma-lactone. Under identical conditions the homologous 2'-deoxy-2'-alpha-C-(carboxyethyl)uridine derivative does not yield the corresponding delta-lactone, but undergoes elimination of uracil to give the corresponding glycal. The pentofuranosyl gamma-lactone is a good substrate for nucleoside synthesis by the Vorbrüggen procedures and undergoes completely stereoselective ring opening with either pyrimidine or purine silylated nucleobases to give novel 2'-C-carboxymethyl beta-nucleosides in moderate to high yield.
authors.affiliation: Department of Chemistry, University of Liverpool, Crown St., Liverpool, UK L69 7ZD.
authors.forename: Volker
authors.initials: V
authors.lastname: Fehring
authors.forename: Sally
authors.initials: S
authors.lastname: Knights
authors.forename: Mai-Yee
authors.initials: MY
authors.lastname: Chan
authors.forename: Ian A
authors.initials: IA
authors.lastname: O'Neil
authors.forename: Richard
authors.initials: R
authors.lastname: Cosstick
mesh_terms: D002625:Chemistry, Organic / Q000379:methods; D007783:Lactones / Q000737:chemistry*; D013058:Mass Spectrometry; D008956:Models, Chemical; D009705:Nucleosides / Q000737:chemistry*; D014498:Uracil / Q000737:chemistry
chemical_list: D007783:Lactones; D009705:Nucleosides; D014498:Uracil