| Abstrakt: |
An efficient method for the synthesis of nucleoside 3'-C-methylenephosphinates, building blocks for oligo(ribonucleoside methylenephosphonate)s, has been developed. Treatment of bis(trimethylsilyl)hypophosphite (BTSP) with a 3'-deoxy-3-C-(iodomethyl)uridine resulted both in substitution to give the corresponding 3'-C-methylenephosphinate and in reduction of the iodomethyl group to afford the uridine 3'-deoxy-3'-C-methyl derivative. Optimisation of solvent and temperature gave a substitution/reduction ratio of 5:4 at best. Through the use of a trifluoromethanesulfonyl leaving group and further optimisation of reaction conditions, however, the triethylammonium 2'-O-(tert-butyldimethylsilyl)-3'-deoxy-5'-O-(4-methoxytriphenylmethyl)uridine-3'-C-methylenephosphinate was obtained in 93% isolated yield. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002) |
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