Synthesis of 2′,3′-didehydro-2′,3′-dideoxynucleosides via nucleoside route

2',3'-Didehydro- and 2',3'-dideoxynucleosides are both potent antiviral agents. In particular, they are Nucleoside Reverse Transcriptase Inhibitors and hence active against HIV, the ethiological agent of AIDS. They are also intermediates for the synthesis of antiviral 2',3'-dideoxynucleosides. Various aspects of synthetic routes to 2', 3'-unsaturated nucleosides are reviewed with examples being chosen from work published between 1966 and 2003.