Efficient syntheses of 1-bromodeoxy-, 1-azidodeoxy- and 1-aminodeoxypentitols from unprotected d-pentono-1,4-lactones

The reduction of unprotected 5-bromo-5-deoxy-d-ribono, d-arabinono and d-xylono-1,4-lactones was achieved with NaBH4 in water–EtOH. The corresponding 1-bromo-1-deoxypentitols were isolated after acetylation in good overall yields (60–90%). 1-Azido-1-deoxypentitols were obtained quantitatively either by nucleophilic substitution by azide ion and deacetylation of the corresponding monobromopentitols or by reduction of the corresponding 5-azido-5-deoxy-d-pentono-1,4-lactones. The reduction of the monoazidopentitols by catalytic hydrogen transfer gave the monoaminopentitol analogues in quantitative yield.