Synthesis and configurational assignments of 3-substituted 2-deoxy-4-thio-D-erythro-pentafuranose derivatives

A new route is described to 1-O-acetyl-2-deoxy-4-thio-α,β-D-erythro-pentofuranose derivatives starting from L-arabinose. This route is amenable to variation in the 3-substituent and the 3-O-benzoyl and 3-azido derivatives were obtained in 17 and 15% yields, respectively, making this procedure easily the most economical entry to 4′-thionucleosides. The anomeric configuration of these and other thiosugars is established unequivocally.