US Patent 7521568 Enantiopure 4-deoxypentenosides, dihydropyrans and tetrahydropyrans and syntheses thereof

Enantiopure substituted 4-deoxypentenosides (4-DPs) and related dihydropyrans (DHPs) are prepared from common carbohydrates via a novel process. The 4-DPs and related DHPs are amenable to a broad range of stereoselective transformations and are used as synthetic intermediates to prepare a variety of enantiopure tetrahydropyrans (THPs), including rare or exotic sugars and other complex THPs of commercial or medicinal value. In one embodiment of the instant invention, 4-DPs are converted to L-sugars in a novel process that offers distinct advantages over known synthetic methods.