SYNTHESIS OF MEDIUM AND LARGE RINGS, XLVI - SYNTHESIS AND REACTIONS OF OPTICALLY-ACTIVE BRIDGED DEOXYFURANOSE DERIVATIVES

Treatment of the bridged methyl furanosides 1, 3 and 5 with dilute aci d furnishes the corresponding deoxyfuranose derivatives 2, 4 and 6. Th e trans-substitution pattern of the tetrahydrofuran ring was establish ed by X-ray structural analysis of 2 and by comparison of the H-1-NMR spectra. A new resolution procedure for rac-3 via the dicamphanoates ( +)-7 and (-)-7 is reported. The hemiacetals (+)-6 and (-)-6 dimerize r eadily under elimination of water in chloroform to give the bridged di saccharides (+)-8 and (-)-8, respectively.