Deoxygenation/dimerization of sugar derivatives with BF3·Et2O–Et3SiH: synthesis of a β-isonucleoside

Lewis acid-Et3SiH induced deoxygenation of anomeric carbon of sugars generates tetrahydrofuran derivatives, accompanied by hitherto unknown dimeric products. If the reagent addition steps are reversed, tetrahydrofuran derivatives are obtained as the sole products, while only the dimeric products are isolated if Et3SiH is excluded. One of the deoxygenated products has been transformed into a β-isonucleoside.