6-Deoxypenciclovir (I) was reacted with trimethyl orthoacetate in the presence of p-toluenesulfonic acid to give the cyclic orthoacetate intermediate (II) which, after aqueous quenching, afforded monoacetate ester (III). Subsequent treatment of (III) with isopropyl p-nitrophenyl carbonate (IV) using a catalytic amount of dimethylaminopyridine provided the target carbonate ester.