Synthesis of 1,2-anhydro-3,4,5-tri-O-benzyl-β-D-fructopyranose

Article abstract of DOI:10.1016/0008-6215(94)84289-2

A synthesis of the anomeric spiro-epoxide 15 from D-fructose, in 7 steps in an overall 13percent yield, is described.The key intermediate in the synthesis, 3,4,5-tri-O-benzyl-1-deoxy-1-iodo-β-D-fructopyranose (14), was prepared from the corresponding methyl fructopyranoside by reaction with the iodine-triphenylphosphine-imidazole reagent complex, followed by acid hydrolysis.Ring closure of the iodohydrin 14 was achieved under extremely mild conditions on treatment with silver(I) oxide in anhydrous THF.The 13C NMR spectrum of 15 exhibited a large upfield shift of the resonances assigned to C-1 and C-2, indicative of an oxirane ring involving these two carbon atoms.