Stereoselective synthesis of 4'-carbon-substituted xylofuranosyladenines.

School of Pharmaceutical Sciences, Showa University, 1-5-8 Hadanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Nucleic Acids Symposium Series 02/2004; DOI: 10.1093/nass/48.1.47
Source: PubMed


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.

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