Preparation of 2,5-Anhydrohexitols (Part Ii). Intramolecular Nucleophilic Substitution of Cyclic Sulfates

ABSTRACT The 2-O-acetyl-3,4-di-O-benzyl-5,6-O-cyclic sulfates 5, 16 and 25, derived from D-arabinose, D-ribose and D-xylose, respectively, are useful precursors in the synthesis of 2,5-anhydrohexitols. 5-Exo-tet cyclization of compounds 5, 16, and 25 under the influence of base leads to the predominant or exclusive formation of the corresponding tetrahydrofuran derivatives