Application of oxazolidinone alpha-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-alph a,beta-unsaturated imide (+)-9 with N-fluorobenzene-sulfonimide (NFSi) affo rded the E-beta,gamma-unsaturated alpha-fluoro imide (+)-10 as a single dia stereoisomer. Dihydroxylation resulted in the formation of 2-fluoro-2-deoxy -gamma-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). (C) 2000 Elsevier Science L td. All rights reserved.