Synthesis of 2′,3′-Dideoxy-D-erythro-hexofuranosyl Nucleosides and 3′-Azido-2′, 3′-dideoxy-D-arabino-hexofuranosyl Nucleosides From Tri-O-acetyl-D-glucal via an α,β-Unsaturated Hexose Aldehyde

α,β-Unsaturated aldehyde 2 prepared from tri-O-acetyl-D-glucal was acetalated and benzoylated to give α,β-unsaturated acetal 6. Hydrogenation of the double bond followed by methanolysis resulted in methyl 2,3-dideoxyfuranosyl glycoside 8 which was used for nucleoside coupling with silylated N ⁶-isobutyrylcytosine and silylated thymine. Protected 3-azido-2,3-dideoxy-arabino-furanose 26 was prepared by 1,4-addition of hydrazoic acid to disilylated α,β-unsaturated aldehyde 24 followed by acetylation. Compound 26 was used for the preparation of 3′-azido-2′,3′-dideoxy-D-arabino-hexofuranosyl nucleosides 28 and 29.