Synthesis of a 1′-α-phenylselenouridine derivative as a synthetic precursor for various 1′-modified nucleosides, via enolization at the 1′-position of 3′,5′-O-TIPDS-2′-ketouridine

Synthesis of the 1′-α-phenylselenouridine derivative 1α, a potentially useful precursor for the synthesis of a variety of 1′-modified nucleosides, was achieved via enolization of the 3′,5′-O-TIPDS-2′-ketouridine 2. Successive treatment of 2 with LiHMDS and PhSeCl at ≤70°C in THF gave the corresponding 1′-phenylseleno product, which was reduced stereoselectively with NaBH4/CeCl3 in MeOH to give the target compound 1α.