2-Deoxy-P-~-ribo-hexopyranosyl nucleosides with adenine (2), hypoxanthine (17), guanine (23), cytosine (13), and uracil (7) as the aglycon were synthesized by the Lewis-acid- catalyzed condensation of an appropriate trimethylsilylated heterocyclic base and 2-deoxy- 1, 3, 4, 6-tetrakis-0-(4-nitrobenzoyl)-/3-~-ribo-hexopyranose (5) to provide the desired/3 anomers in good yield. When the synthesis of 7 via an SN2 displacement was attempted ...