The reaction of silylated (S)-glycidol (I) with the vinyl copper compound (II) in ethyl ether gives the monosilylated unsaturated diol (III), which is desilylated with Bu4NF in THF yielding the diol (IV). The cyclization of (IV) by means of I2 and NaHCO3 in acetonitrile affords a mixture of the cis and trans diastereomers from which the trans isomer (V) was isolated. The acylation of (V) with potassium 4-nitrobenzoate (VI) in DMSO/18-crown-6 yields the 4-nitrobenzoyl ester (VII), which is condensed with adenine (VIII) by means of DEAD and triphenylphosphine in DMF providing the 4-nitrobenzoyl percursor (IX). Finally, (IX) is debenzoylated with NaOMe in methanol.