SYNTHESIS OF MEDIUM AND LARGE RING COMPOUNDS .41. SYNTHESIS AND REACTIONS OF OPTICALLY-ACTIVE BRIDGED METHYL DEOXYFURANOSIDES

The resolution of the earlier reported racemic bridged methyl deoxyfur anosides 1 and 3 was achieved via fractional crystallization of the ep hedrinium salts 2 or by column chromatography of the camphanoates 5. T he absolute configurations of 1 and 3 were established by X-ray struct ural analysis of the (S)-alpha-naphthylethylammonium carboxylate (+)-4 and by correlation with the other enantiomerically pure compounds of this type. (+)-3 was converted in to the 2,5-bridged altrose derivativ e (+)-8.