Regioselective Dehydration of Sugar Thioacetals under Mild Conditions

Abstract

Pentose and hexose sugars are abundant constituents of waste biomass, making them sustainable, chiral building blocks for organic synthesis. The demand for chiral saturated heterocyclic rings from the pharmaceutical industry is increasing as they provide well-defined three-dimensional frameworks that show increased metabolic resistance. Through the formation of thioacetals, sugars may be manipulated in their straight-chain form and dehydrated selectively under basic conditions at C-2. This approach was applied to an array of sugars and extended to the production of useful chiral THFs via further selective dehydration reactions.

Regioselective Dehydration of Sugar Thioacetals under Mild Conditions

“…In summary, we have developed scalable methods for the regioselective C-2 dehydration of sugar thioacetals. 28 The resulting ketene thioacetals are versatile synthetic intermediates 29 which can be used to access polyols containing a stereogenic center bearing an ethyl group. Preliminary studies have also demonstrated that further selective dehydration reactions and cyclization of these compounds can be used to access chiral heterocycles (THFs, butyrolactones) that are useful building blocks for asymmetric synthesis.…”

“…In summary, we have developed scalable methods for the regioselective C-2 dehydration of sugar thioacetals. 28 The resulting ketene thioacetals are versatile synthetic intermediates 29 which can be used to access polyols containing a stereogenic center bearing an ethyl group. Preliminary studies…”