2,3-Dideoxy-furanoses in Convergent Syntheses of 2′,3′-Dideoxy Nucleosides

Convergent syntheses, in which a synthetic 2,3-dideoxy-furanose intermediate is condensed with a synthetic base with the aim of producing 2′-substituted-, 3′-substituted- or unsubstituted-2′,3′- dideoxy nucleosides - potential HIV inhibitors - are reviewed. It is demonstrated that this approach provides a potential for structural variations, including unnatural configurations, otherwise unattainable. Starting from both carbohydrate and noncarbohydrate precursors synthetic routes to the carbohydrate moiety are emphasized and syntheses of related compounds considered. 1. Introduction 2. 2′,3′-Dideoxy Nucleosides 2.1. Syntheses having Tetrahydrofuran Derivatives as Precursors 2.2. Synthesis having Glutamic Acid as the Precursor 2.3. Syntheses having Mannitol or Ribonolactone Derivatives as Precursors 2.4. Syntheses having Ribose Derivatives as Precursors 2.5. Related Syntheses of 2,3-Dideoxy Sugars 3. 3′-Azido-2′,3′-dideoxy Nucleosides 3.1. Syntheses having D-Mannitol as the Precursor 3.2. Synthesis having D-Xylose or 2-Deoxy-D-ribose as the Precursor 3.3. Syntheses having L-Arabinose or Tri-O-acetyl-D-glucal as the Precursor 3.4. Related Syntheses of 3-Azido-2,3-dideoxy Sugars 4. 3′-Amino-2′,3′-dideoxy Nucleosides 4.1. The Phosphorus Pentoxide Reagent 4.2. Synthesis of and Coupling with 2,3-Dideoxy-3-phthalimido-erythro-pentofuranose Derivatives 4.3. Synthesis of and Coupling with 2,3-Dideoxy-3-phthalirnido-D-hexofuranose Derivatives 4.4. Related Syntheses of 3-Amino-2,3-dideoxy-hexofuranose Derivatives 5. 2′,3′-Dideoxy-3′-substituted Nucleosides 5.1. 3′-Alkyl-2′,3′-dideoxy Nucleosides 5.2. 3′-Cyano-2′,3′-dideoxy Nucleosides 5.3. 2′,3′-Dideoxy-3′-fluoro Nucleosides 5.4. 3′-Alkylthio- and 3′-Arylthio-2′,3′-dideoxy Nucleosides 6. 2′,3′-Dideoxy-2′-substituted Nucleosides 7. Concluding Remarks