Reaction of 4',5'-epoxynucleosides with carbon nucleophiles: stereoselective synthesis of 4'-C-carbon-substituted nucleosides.
4',5'-Epoxythymidine (4) was obtained as a single diastereoisomer by oxidation of 3'-O-(t-butyldimethylsilyl)-4',5'-dehydrothymidine (3) with dimethyldioxirane. When the epoxide 4 was treated with allyltrimethylsilane in the presence of SnCl4, regio- (at the C4') and stereoselective (from the alpha-face) cleavage of the oxirane ring proceeded to afford a 4'-C-alpha-allylated derivative (5) as a sole product. In the reaction of 4 with trimethylaluminum, 4'-C-beta-methyl derivative (8) was obtained as a major product.
Haraguchi
Kazuhiro
K
School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai Shinagawa-ku, Tokyo 142-8555, Japan.
Takeda
Shingo
S
Tanaka
Hiromichi
H
D002244:Carbon / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D009705:Nucleosides / Q000138:chemical synthesis / Q000737:chemistry*
D004852:Epoxy Compounds; D009705:Nucleosides; D002244:Carbon