Synthesis of pyrimidine 1′-fluoronucleosides

Treatment of the 1′-lithium enolate, prepared from a 2′-ketouridine derivative, with NFSI, followed by reduction of the 2′-keto-moiety gave the corresponding 1′-fluorouridine derivative and its arabino-type congener. Thus, the first synthesis of 1′-fluoronucleosides was achieved.