A novel type of nucleotide analogues, the 2′,3′-O-(1-diethylphosphono)alkylidene derivatives of ribonucleosides was prepared by redox reaction of diethyl chlorophosphite with various nucleoside orthoesters. Some of these compounds undergo interesting rearrangements when treated with nucleophiles. The configuration of the title compounds was determined by 2D-ROESY experiments. Biological activity of
Various 3′,5′-O-(1-phosphonoalkylidene) derivatives of 1-(2-deoxy-β-D-threo-pentofuranosyl)thymine bearing a substituent in the ω-position of the alkylidene chain were prepared by the redox reaction of diethyl chlorophosphite with six-membered 3′,5′-orthoesters of xylo-dT. Susceptibility of ω-haloalkylidene derivatives for nucleophilic substitution is discussed. The configuration of the final phosphonates