Application of Oxazolidinone α-Fluoro Amide Chiral Building Blocks in the Asymmetric Synthesis of Fluorinated Carbohydrates: 2-Deoxy-2-fluoropentoses

Deconjugative electrophilic fluorination of the lithium dienolate of Z-α,β-unsaturated imide (+)-9 with N-fluorobenzenesulfonimide (NFSi) afforded the E-β,γ-unsaturated α-fluoro imide (+)-10 as a single diastereoisomer. Dihydroxylation resulted in the formation of 2-fluoro-2-deoxy-γ-xylonic and -lyxonic lactones, 12a and 12b, respectively. Reduction and deprotection of the lactones afforded 2-deoxy-2-fluoro-xylo-d-pyranose (15) and 2-deoxy-2-fluoro-lyxo-l-pyranose (17).