Uracil Nucleosides with Reactive Group at C5 Position: 5-(1-Halo-2-sulfonylvinyl)uridine Analogues.

The transition-metal-catalyzed or radical-mediated halosulfonylation of 5-ethynyluridine provided (E)-(1-halo-2-tosylvinyl)uridines. These (β-halo)vinyl sulfones undergo efficient stereoselective addition-elimination with amines or thiols to provide Z-β-aminovinyl or E-β-thiovinyl sulfones tethered to the C5 position of the uracil ring.