Convenient preparation of 3,5-anhydro- and 2,5-anhydropentofuranosides, and 5,6-anhydro-D-glucofuranose by use of the Mitsunobu reaction.

Methyl 3,5-anhydro-alpha-D-xylofuranosides are obtained by use of the Mitsunobu reaction from 2-O-protected methyl alpha-D-xylofuranosides, which are easily prepared from D-xylose. The Mitsunobu reaction of methyl 3-N-benzylamino-3-deoxy- and 3-azido-3-deoxyarabinofuranosides, which are prepared from the conveniently available methyl 2,3-anhydro-alpha-D- and 2,3-anhydro-alpha-l-lyxofuranosides by nucleophilic ring opening, yields the corresponding methyl 2,5-anhydro-alpha-D- and 2,5-anhydro-alpha-l-arabinofuranosides. Ring opening of 3,5-anhydro-1,2-O-isopropylidene-alpha-D-xylofuranose with azide yields the corresponding 5-azido derivative. The structure and configuration of the products is confirmed by NMR spectroscopy. 5,6-Anhydro-1,2-O-isopropylidene-alpha-D-glucofuranose is formed by the Mitsunobu reaction of 1,2-O-isopropylidene-alpha-D-glucofuranose. Its structure is verified by single-crystal X-ray diffraction analysis.