Abstract
The products obtained by titanium tetrachloride mediated dithioacetalization of four pentofuranoside derivatives were converted to thiofuranose sugars, either by direct cyclization via the unstable triflate intermediate, or by treatment of the derived mesylate. A facile inversion of a D-ribose dibenzyl dithioacetal 9 to an L-lyxose dibenzyl dithioacetal 12 via hydrolysis of the Mitsunobu derived formate intermediate is also described.