Deoxysugars via Microbial Reduction of 5-Acyl-isoxazolines: Application to the Synthesis of 3-Deoxy-d-fructose and Derivatives

5-Acylisoxazolines 3a−d were obtained by 1,3-dipolar cycloaddition from acetoxymethyl vinyl ketone and nitro precursors. Compounds 3a−d were biotransformed by Aspergillus niger into a 1:1 mixture of stereomers of 5-dihydroxyethyl isoxazolines (+)-4a−d (anti) and (−)-5a−d (syn). Both stereomers were obtained in good yields and with high optical purities. Carbonyl reduction by Aspergillus niger produces alcohols of R-configuration thus giving an access to d-sugar analogues: Compound (+)-4d was converted to 3-deoxy-d-erythro-hexulose and several protected derivatives. Total synthesis of 3-deoxy-d-fructose-6-phosphate was also achieved in two steps and 64% overall yield from (+)-4d.