Regioselective Dehydration of Sugar Thioacetals under Mild Conditions.

Sugars are abundant in waste biomass, making them sustainable chiral building blocks for organic synthesis. The demand for chiral saturated heterocyclic rings for pharmaceutical applications is increasing as they provide well-defined three-dimensional frameworks that show increased metabolic resistance. A range of sugar thioacetals can be dehydrated selectively at C-2 under mild basic conditions, and the resulting ketene thioacetals can be applied to the production of useful chiral building blocks via further selective dehydration reactions.