title: Stereoselective synthesis of 4'-carbon-substituted xylofuranosyladenines.
abstract: Epoxidation of 2',5'-bis-O-silyl-protected N6-pivaloyl-3',4'-unsaturated adenine nucleosides (1, 2 and 3) with dimethyldioxirane uniformly proceeded face-selectively to give the respective 3',4'-beta-epoxides (4, 5 and 6). Ring cleavage of these epoxides examined with Me3Al in CH2Cl2 showed that the TBDMS (4) or TES (5) protected epoxide gave the desired 4'-alpha-methylated product (8 or 10) as the major stereoisomer, while use of the TBDPS protected epoxide (6) resulted in reverse stereoselectivity. Reactions of 4 with other organoaluminum reagents were also carried out.
authors.affiliation: School of Pharmaceutical Sciences, Showa University, 1-5-8 Hadanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kubota
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Haraguchi
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kunikata
authors.forename: Mari
authors.initials: M
authors.lastname: Hayashi
authors.forename: Masaomi
authors.initials: M
authors.lastname: Ohkawa
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013237:Stereoisomerism; D013343:Styrenes / Q000737:chemistry
chemical_list: C506477:4-(tert-butyldimethylsiloxy)styrene; D012821:Silanes; D012833:Siloxanes; D013343:Styrenes; C512918:triethylsilane; D002244:Carbon; D000241:Adenosine