title: Stereo- and regioselective radical cyclization of 6-(bromomethyl)dimethylsilyl-1',2'-unsaturated uracil nucleosides: synthesis of 1'-alpha-hydroxymethyl nucleosides.
abstract: Mode of radicalcyclization (5-exovs. 6-endo) was investigated by using 6-(bromomethyl)dimethylsilyl derivatives of 1',2'-unsaturated uridine with an aim to develop a new stereoselective method for the introduction of an alpha-hydroxymethyl group at the anomeric position. Although the 2'-unsubstituted derivative underwent only 6-endo-cyclization, substrates bearing 2'-CO2Me or 2'-OBz group gave exclusively 5-exo-cyclized products with a high stereoselectivity.
authors.affiliation: School of Pharmaceutical Sciences, Showa University, 1-5-8 Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Ogamino
authors.forename: H
authors.initials: H
authors.lastname: Kumamoto
authors.forename: H
authors.initials: H
authors.lastname: Mizunuma
authors.forename: S
authors.initials: S
authors.lastname: Takeda
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D017605:Bromine Compounds / Q000737:chemistry; D003500:Cyclization; D006900:Hydroxylation; D008745:Methylation; D017646:Organosilicon Compounds / Q000737:chemistry; D011741:Pyrimidine Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D017605:Bromine Compounds; D017646:Organosilicon Compounds; D011741:Pyrimidine Nucleosides; D014498:Uracil