Conversion of d-xylose to protected d-lyxose derivatives and to d-lyxose, via the corresponding 1,2-anhydride

Acid hydrolysis of 3,5-di-O-benzyl-1,2-O-cyclohexylidene-α-d-xylofuranose gave the corresponding lactol, which was subsequently converted to the 3,5-di-O-benzyl-2-O-mesyl-d-xylofuranose. This compound readily reacted with sodium methoxide, sodium benzylate or sodium hydroxide (presumably via the corresponding 1,2-anhydride) to give the protected d-lyxofuranosides. These compounds were finally converted to methyl α-d-lyxopyranoside or to d-lyxose.