合成路线1

The protection of the chiral epoxy-alcohol (I) with Pmb-Cl, NaH and tetrabutylammonium iodide (TBAI) gives the protected compound (II), which is condensed with 2-amino-6-(2-methoxyethoxy)purine (III) in hot DMF to yield the adduct (IV). Elimination of the OH group of (IV) by means of a treatment with phenyl chlorothioformate, followed by a thermal elimination reaction with Bu3SnH and AIBN, affords the carbocyclic purine (V). The selective deprotection of (V) with DDQ in dichloromethane provides the cyclopentanol derivative (VI), which is treated with MsCl and DMAP to give the mesylate (VII).The reaction of (VII) with sodium 2-methoxyethanolate (A) in DMF yields the cyclopentene derivative (VIII), which is treated with AlI3 in hot acetonitrile to afford the carbocyclic guanine derivative (IX). The deprotection of (X) with BF3/Et2O and Ac2O provides the diacetyl derivative (X), which is finally deacetylated to the target chiral compound by means of NH3 in methanol.