Concise and stereospecific synthesis of novel bicyclic dideoxynucleosides as potential antiviral agents
A novel class of dideoxynucleosides containing a bicyclic sugar moiety, structurally related to the natural griseolic acids, was synthesized starting from the stereochemically defined compound, 1,4:3,6-dianhydro-D-glucitol. The key intermediate in the synthesis was a [3.3.0] fused bicyclic glycal. Glycosylation of this compound with nucleobase proceeded both regiospecifically and stereospecifically in the presence of an auxiliary agent, N-iodosuccinamide. Changes in stereochemistry during the synthesis was monitored by optical rotation data and confirmed by both 1D and 2D NMR experiments. The synthetic approach described possesses general usefulness.