合成路线1

The aldehyde (XIII) is submitted to a Wittig condensation with N-acetyl-2-(diphenylphosphoryl)glycine (XIV) and potassium tert-butoxide in dichloromethane giving a mixture of the (Z)- and (E)-isomers (XV) and (XVI), respectively. The regiocontrolled hydrogenation of this mixture with H2 over a chiral rhodium catalyst in methanol yields the saturated (S,S)-isomer (XVII), which is submitted to a selective deprotection of its sugar moiety, followed by acetylation of the resulting free hydroxy groups with acetic anhydride in dioxane to afford the triacetoxy compound (XVIII). The condensation of (XVIII) with N6-benzoyladenine (XIX) by means of trimethylsilyl trifluoromethanesulfonate gives the adenosine derivative (XX), which is treated with K2CO3 and hydrazine to eliminate the acetyl and benzoyl groups yielding (XXI). Finally, this compound is debenzylated by hydrogenation with H2 over Pd/C in methanol.